Thermal imagers are developed from photosensitive components that are sensitive to infrared rays, but the photosensitive components can only judge the presence of infrared rays and cannot present images. Warring nations in World War II showed interest in the military use of thermal imagers, conducting sporadic research and small-scale applications.

[2] In 1952, indium antimonide was developed, a new semiconductor material that facilitated the further development of infrared thermal imagers. Soon after, Texas Instruments developed a practical Forward looking infrared thermal imager. This system uses single-element photosensitive, and uses mechanical equipment to control the rotation of the lens to reflect light onto the photosensitive component.

[3] With the maturity of the mercury cadmium telluride material manufacturing process, the large-scale adoption of thermal imagers in the military field has become possible. After the 1960s, a linear array of 60 or more photosensitive components appeared, and the Swedish company AGA expanded the application of thermal imagers to the civilian field. However, due to the initial use of uncooled photosensitive components, the refrigeration components plus the mechanical scanning mechanism make the entire system very large.

 

[4] When the CCD technology matures, the focal plane array thermal imager replaces the mechanical scanning thermal imager. In the 1980s, after semiconductor refrigeration technology replaced liquid nitrogen and compressor refrigeration, portable, hand-held thermal imagers began to appear. After the 1990s, Texas Instruments developed an uncooled infrared focal plane array based on amorphous silicon, which further reduced the production cost of thermal imagers.