Figure 2 provides an example of the detail available with thermal imaging. The cursor shows the temperature at a point on one of the PGA devices. The temperature on the case is 108.5 C. Note the flow of heat from the devices into and across the board. The lower the thermal resistance to heat flow the lower the temperature. Conversely, if the resistance is high, the junction temperature will be hotter.
Thermal images are pictures of heat rather than light.
K radiates infrared energy. The amount of this radiated power is determined by the following equation. An IR thermal imager captures a portion of this radiated energy and provides a calibrated temperature presentation. Through a variety of scanning techniques, a spatial map of temperatures is generated and displayed or saved as a computer file. The computer-compatible file format is available for subsequent manipulation, display or for process control.