Optotherm, Sewickley, Pa., has developed the EL troubleshooting system, which provides an alternative method of fault detection based on detection of infrared radiation. As circuit boards are powered, they emit electromagnetic (EM) energy in a broad spectrum of wavelengths and in an amount that is proportional to their temperature. As the temperature of a board increases, the amount of EM energy it emits also increases, with almost all in the infrared spectrum, and with wavelegths between 1 and 1000µm.
Optotherm’s cameras are able to detect this infrared energy and create two-dimensional images that display the infrared energy emanating from various points on a circuit board. These images represent the temperature distribution over the surface of the board. Optotherm infrared cameras are sensitive to a specific band of the infrared spectrum between 7 and 14µm in wavelength. The majority of infrared energy emitted by circuit boards with temperature below 200°C is within this wavelength band.
EL is an effective and economical tool that can isolate defects that fall in the gaps between conventional inspection and debugging techniques, and thereby can reduce debugging costs and minimize scrap. When used as the first screen of defective boards, EL can quickly provide useful troubleshooting information, dramatically reducing time to repair.
EL can also be used to inspect boards for basic functionality. Although EL cannot provide the same detailed level of functional verification as a functional test, it can provide verification of basic board operation. Advantages of EL over traditional functional testers include low cost and fast setup. No custom hardware is required, and tests can usually be setup in less than an hour. EL is ideal when the high cost of a dedicated functional tester cannot be justified.
http://www.optotherm.com/el-intro.htm
