Uncooled LWIR Lens

https://www.cngeir.com/products/uncooled-lwir-lens/

The Uncooled LWIR lens is a specially designed optical lens for imaging systems in the long wave infrared (LWIR) band, such as thermal imagers. Uncooled infrared refers to the technology or method used in the design of an uncooled LWIR lens so that the imaging performance of the uncooled infrared lens is not affected by temperature changes. This uncooled LWIR lens can maintain a stable focal length when the temperature changes, without external adjustment to compensate for the temperature-induced changes in image quality.