MWIR Lens Applications

With the development and application of infrared detector technology, the use of mid-wave infrared lenses is also increasing. Due to the refrigeration core used in the medium wave, the efficiency of the cold aperture can reach 100%, and the evaluation indicators such as the clarity of the photoelectrically converted image, the signal-to-noise ratio, and the minimum resolution temperature difference will be significantly improved compared to the uncooled long-wave imaging. The medium and long wave is mainly temperature thermal imaging, which converts the spatial distribution of infrared radiation generated by the scene due to different temperature and emissivity into a video image. The difference between medium and long wave imaging is that the temperature is low to close to normal temperature and suitable for long wave detection, while the temperature is slightly higher. suitable for detection with medium waves. The medium wave infrared imaging lens has the characteristics of good shading, can work day and night, and has a strong ability to penetrate smoke and dust at the same time, especially suitable for long-distance remote monitoring. Silicon is the most commonly used material in the field of mid-wave infrared optical systems (3-5um). The overall trend is to require optical systems to be small in size, light in weight, and simple in structure. Usually, aspherical surfaces are used on silicon lenses to cause diffractive surfaces; silicon aspherical surfaces, diffractive surfaces The surface is not easy to process from time to time. The reason is that the physical properties of silicon materials are brittle and hard, and it is often easy to cause problems such as chipping during processing. It is also difficult to control the surface brightness and surface accuracy. The cost also makes the silicon aspheric and diffractive lenses very expensive, so that the silicon aspheric and diffractive surfaces stay in the stage of a small number of samples from time to time, and cannot be widely used. In the application of medium wave, the continuous zoom lens is widely used, which can stop the detection of different fields of view, and the medium wave imaging generally uses a cooling type movement, the image quality will be very good, and it is widely used in remote and accurate monitoring.