Due to the expensive materials of the refrigerated infrared detector and the low yield of the detector, the refrigerated infrared imaging system is expensive; at the same time, the refrigerated infrared imaging system requires a set of refrigeration equipment, which increases the system cost and reduces the reliability of the system. In addition, the cooling infrared imaging system has high power consumption, large size, and bulkiness, and it is difficult to achieve miniaturization, which limits the wide application of the cooling infrared imaging system.

Uncooled infrared focal plane detector arrays have the advantages of room temperature operation, no refrigeration, spectral response independent of wavelength, relatively simple preparation process, low cost, small size, easy to use, good maintenance and reliability, etc., thus forming a new rich The development direction of Vitality aims to achieve excellent infrared imaging performance at lower cost, smaller size and lighter weight. In recent years, three different types of uncooled infrared focal plane detector arrays have been successfully developed. The physical mechanisms of these three different types of uncooled infrared focal plane detector arrays are as follows:

(1) The thermopile detects the temperature gradient between the hot end and the cold end according to the Seebeck effect, and the signal is in the form of voltage.

(2) The bolometer detects changes in carrier concentration and mobility caused by temperature changes, and the signal is in the form of resistance. (3) Pyroelectric detection temperature changes cause changes in dielectric constant and spontaneous polarization, and the signal form is charge. Among the three different types of uncooled infrared focal plane detector array devices, bolometer arrays have developed the most rapidly and have achieved remarkable achievements. It is fabricated by silicon micromachining technology similar to silicon technology. In order to achieve effective thermal insulation, a bridge structure is generally used. The electrical interconnection between the detector and the silicon readout circuit is achieved through two support legs. The sensitivity of a bolometer mainly depends on its thermal insulation from the surrounding medium, i.e. thermal resistance, the greater the thermal resistance, the higher the attainable sensitivity. The current temperature resolution of bolometer arrays can reach 0.1K. Uncooled bolometer array technology is an advance in infrared imaging technology over the past 20 years. 00 French Sofradir Company produced the first uncooled focal plane infrared detector, the detector array size is 320x240 yuan, the pixel center distance is 45pm, the fill factor is greater than 80%, and the noise equivalent temperature difference (NET D) reaches 01K (typical value) , the performance index of the device has reached the advanced level in the world today.