Infrared lenses are classified mainly in three kinds in terms of wavelength range. Short-Wave Infrared (SWIR) Lenses, with a wavelength of about 1-3μm. Mid-Wave Infrared (MWIR) Lenses, in the 3-5μm range. Long-Wave Infrared (LWIR) Lenses, operating at 8-14μm.

IR lenses have a wide range of applications. In industrial areas, mid-wave lenses are used to monitor high-temperature processes such as steel smelting, guaranteeing product quality, while long-wave lenses detect heat in industrial machinery, helping to identify potential malfunctions early. For security and surveillance, mid-wave lenses are excellent for outdoor night-vision, being able to penetrate fog and dust, and long-wave lenses are utilized in perimeter security, sensing human body heat from a distance to trigger alarms. In medical and healthcare, long-wave lenses play a role in medical thermography, assisting doctors in detecting abnormal body heat related to diseases like breast cancer for more accurate diagnoses. In environmental and scientific research, these lenses are used to study surface temperature, vegetation, and water quality in environmental monitoring, and mid-wave lenses help observe infrared-emitting celestial objects in astronomy.