Infrared thermal imaging is widely used in defence and planetary science applications. Increasingly, long-wave infrared thermal imaging has been used in consumer applications such as security cameras, advanced fire detection and suppression, smart appliances, and self-driving cars. The lenses in these thermal imaging cameras, however, are cost-limiting in many cases because they are made from restricted materials such as germanium. These lenses are also manufactured by slow milling processes. There is a need for alternative IR optics that are low cost and amenable to high-throughput manufacture. Polymers made from sulfur have been recently explored to meet this need, with their high refractive index and long-wave IR transparency imparting the required optical properties for lenses used in thermal imaging.[1] These advances, however, are still limited in optical performance, thermal stability, and manufacturing methods.
In this report, we describe low-cost polymers made from sulfur and organic dienes and their use in thermal imaging applications.[2] The first demonstration of all-polymer optics in thermal imaging at ambient temperature is presented, with images and video that approach the performance of germanium and silicon lenses. These polymers are made from building blocks that are orders of magnitude cheaper than germanium and other inorganic optics. High volume manufacturing methods will also be presented. Other benefits include the capacity to repair and recycle the polymers, which improves sustainability. Prospects in uptake in the thermal imaging market for both civilian and defence applications will be discussed.