TROUBLESHOOT PCB & ELECTRONIC PRODUCT DESIGN WITH THERMAL IMAGING
Finding and fixing hot spots in electronics R&D is a guessing game if you’re not working with a thermal imaging camera. FLIR infrared (IR) cameras for research, development, and science allow you to see temperatures across an entire target, so you can quickly identify heat dissipation problems and begin working on solutions.
FLIR’s R&D/Science infrared camera solutions offer the sensitivity, spatial resolution, frame speed, and integration time needed to capture fast temperature changes and take pinpoint accurate temperature readings on targets with motion.
Importance of Heat Inspection
As electronic circuit boards and components get smaller and more powerful, inherent heat can cause significant damage. Infrared thermography can identify hot spots, allowing for improved thermal management and greater advances in circuit board design.
Electronics don’t like it hot. That’s why electronic systems designers are looking for ways to keep their components cool while the sizes of their devices shrink. As chips get smaller and their densities within components grow, heat can become a real problem—not only for devices used in civilian life, but in the military as well. In the latter case, the problem expands beyond inconvenience to one of safety. The armed forces depend on the quality of their electronics to maintain the integrity of weapons and communications systems.
Hot-Spot Analysis
Another common use for infrared thermal cameras among electronics designers and manufacturers is detecting hot spots for failure analysis. In this case, measuring absolute temperatures isn’t as important as finding small hot spots that are causing subtle thermodifferentials. These hot spots can be indicative of failure points or troubles with the device. While passive thermal imaging works well, a technique called “Lock-In Thermography” can improve the sensitivity of the camera by more than 10 times, making it much easier to detect small, subtle hot spots.
Infrared inspection can also help with quality assurance by identifying insufficient solder. Insufficient solder increases circuit resistance at the solder joint and therefore raises the temperature sufficiently to be detected by an infrared camera. A faulty circuit will show up as a different temperature profile from a good one, and that can help determine whether the circuit should pass or fail.
Cost is not an Issue
The cost justification for thermography is growing as electronic components shrink. Today’s infrared cameras offer up to 16 times the resolution of cameras used ten years ago for nearly the same cost. As costs continue to come down, it is probable that thermal infrared cameras will become a standard thermal measurement tool on every test bench, alongside digital multimeters, oscilloscopes, and voltage analyzers. Technology advances will also factor in.
Take Control of Emissivity Challenge
Where testing in electronics inspection is concerned, thermal imaging still has opportunities for advancement. One challenge to thermal imaging is correcting for surface emissivity. Many electronic boards have components with varying emissivities, some of which are shiny, and therefore, have a low emissivity. This makes them more challenging to measure for absolute temperatures. Techniques such as high emissivity coatings, image subtraction, and emissivity mapping are examples of ways to compensate.
In image subtraction, the infrared inspection system software captures an image before the device is energized, in order to create a thermal baseline. That baseline image is then subtracted from subsequent images after the device is turned on, thereby removing the static reflected temperature values, leaving only the true temperature deltas due to the heating of the device. Image subtraction effectively removes all the apparent thermal hot spots due to erroneous static reflected temperatures from lower emissivity devices and lets you focus on true thermal hot spots generated from the device itself.
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