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At present, there are many brands of infrared thermal imaging cores in the market. How to choose a high-quality infrared thermal imaging core? This article will focus on that.
First look at the detector heat-sensitive material: the core of the core.
The infrared focal plane detector is the core of the infrared thermal imaging movement, and it is the key to detect, distinguish and analyze the thermal information of objects, which is equivalent to the human brain. At the heart of the detector is a heat-sensitive material.
Thermosensitive material is an important bridge between sensing infrared radiation and output signal, and its choice has a great influence on the sensitivity (NETD) of the microbolometer. Materials with high temperature resistivity (TCR) and low 1/f noise are preferred, and it is also necessary to consider whether the integration process between the chosen material and the readout circuit is convenient and efficient. The most commonly used heat-sensitive materials today are vanadium oxide (VOx) and polycrystalline silicon (a-Si).
1. Vanadium oxide (VOx)
In the early 1980s, Honeywell of the United States began to study vanadium oxide with military support. Vanadium oxide has a high TCR (about 2%/k ~ 3%/k at room temperature), and its preparation technology is very mature and has been widely used in microbolometer products. The advantages are sharper images, better stability, and less temperature drift.
2. Polysilicon
In 1992, the French Atomic Energy Commission and the Information Technology Laboratory/Infrared Laboratory (CEA2LETI/LIR) began research on polysilicon. The TCR of polysilicon is equivalent to VOx, and the technology is now mature. It has the advantage of being fully compatible with standard silicon processes, but because the polysilicon structure is amorphous and the 1/f noise is higher than VOx, NETDs are generally inferior to VOx.
Compared with vanadium oxide, polysilicon has large noise, poor temperature measurement accuracy and low sensitivity. Because vanadium oxide pixels are precise temperatures, polysilicon is relatively poor due to material growth characteristics. This results in poor temperature measurement accuracy of polysilicon detectors at distant points and more noise in the image.
2. Look at the clarity: The higher the resolution, the clearer the image, the clearer the object, and the better the user experience.
Detector resolution (pixels) is an important indicator of infrared thermal imaging motion clarity, which will directly affect the final imaging effect.
The resolution of the civilian high-end infrared thermal imaging core is 640×512, the infrared image will be very clear and delicate, and objects the size of rabbits can still be distinguished at 500 meters; human body. 1024×768 and 1280×1024 infrared thermal imaging cores, with real megapixel level, also perform well in high-end civilian fields.
Third, look at the core technology: pixel size.
Pixel size is one of the core technologies of the infrared thermal imaging sports industry.
The pixel size continues to break through, and the current mainstream is 17 microns, moving towards 14 microns. There are two 12-micron manufacturers in the world, one of which is in China. As pixel size decreases, 12 microns will facilitate wider adoption of infrared thermal imaging sports.
Fourth, look at the frame rate: the higher the frame rate, the clearer and smoother the picture.
In real-time detection, frame rate is a very important parameter. For moving detection targets, the higher the frame rate of infrared thermal imaging motion, the more coherent the picture, and the better the observation effect, especially for aerial photography.
Due to technical blockade, foreign infrared manufacturers have locked the frequency of movement modules exported to China, and the frame rate is locked at 9Hz. At present, our domestic high frame is 50Hz.
This movement is an uncooled infrared thermal imaging component newly developed by MH Tech with ultra-small size (PCB: 20mm X 20mm) and ultra-low power consumption (minimum power consumption is less than 0.5W). The compact design makes it fully suitable for OEM assembly and Integrated, with a variety of configurations, a variety of optional lenses, and a secondary development kit, which can meet almost all application needs. This movement adopts the original WD enhancement algorithm of Micro Heating Technology, with clear image, wide dynamic display and zero noise image quality. It is most suitable for applications that require lightweight, small, and low-power thermal imaging cores. It has been widely used in sights, security monitoring, maritime lookouts, drones, telescopes, etc.
