Difference between uncooled and cooled infrared detectors

Infrared detectors can be divided into uncooled infrared detectors and cooled infrared detectors according to their different working principles. This article will introduce the differences between the two in terms of working principle, sensitive materials, sensitivity, measurement accuracy, size and power consumption.

1. Working principle

The working principle of the uncooled infrared detector is that the absorbing material accepts infrared radiation and converts it into heat energy, causing the temperature of the sensitive element to increase, thereby causing some physical parameters of the sensitive element to change, and then converting it into an electrical signal through a conversion mechanism.

The cooled infrared detector is based on the photoelectric effect. Infrared thermal radiation changes the carrier concentration of the sensitive material, which causes changes in the electrical signal of the detection image element, and then the electrical signal is processed to obtain a visible infrared thermal image.

2. Sensitive materials

The main materials of uncooled infrared detectors are vanadium oxide (VOx) and amorphous silicon (a-Si), while the main materials of the cooled infrared detector are mercury cadmium telluride (MCT), Type Ⅱ superlattice (T2SL), indium antimonide (InSb) and quantum Wells (QWIPs).

3. Sensitivity and Measurement accuracy

The cooled infrared detector requires a cryocooler to reduce its own temperature, so its sensitivity and measurement accuracy are higher than that of the uncooled infrared detector.

4. Size and power consumption

The cooled infrared detector is larger than the uncooled detector because it requires a cryocooler to reduce the temperature. In addition, because the cooled infrared detector needs a cryocooler to work, it consumes a lot of power consumption, while the uncooled infrared detector has no cryocooler, so it consumes less power.

5. Longevity

The service life of the cooled infrared detector largely depends on the service life of the cryocooler. For example, the service life of the GSTiR stirling cooler is about 10000h.

6. Price

Due to the need for multiple components such as cryocoolers and dewar components, the production cost of cooled infrared detectors is relatively high. However, uncooled detectors are based on the MEMS technology and can be produced in large quantities, and the cost advantage is more significant.

7. Application

Uncooled infrared detector has the characteristics of small size, low cost, clear imaging, etc., so it is widely used in security monitoring, industrial detection, fire alarm, medical and other fields. Cooled infrared detectors are more used in remote detection, scientific research, aerospace and other fields.

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