Infrared night vision thermal imager uses infrared detector and optical imaging lens which can accept the infrared radiation energy distribution of the measured target,then reflects to the light sensor of infrared detector,therefore gets the infrared thermogram.This thermogram corresponds to the object surface's heat distribution.Generally speaking the infrared thermal imager convert this invisible infrared energy of objects to be visible thermal image.Different colors represent different temperature of the measured target.

Thermal imager was found to be used in the second world war at first.At that time all countries started to give attention to the thermal imager's real value in military operations.With the development and application of indium antimonide in 1952, Texas instruments developed the thermal imager which has use value.Thermal imager was mainly used in military at early times.With the development of science and technology, civil thermal imager appears in our life.Different thermal imager is used in various fields due to different sensitivity of temperature,like hunting, forest fire prevention, line inspection, machine repair, the scene of the fire disaster,night safe driving in the heavy fog, etc.