Traditional lenses made of germanium tend to cost hundreds or thousands of dollars and can’t be repaired when damaged—but a lower-cost sulfur polymer lens option is about to become a gamechanger for infrared (IR) thermal imaging cameras because it can be mass produced, repaired, and recycled. Thermal imaging is currently used for applications like defense, security cameras, driver-assist functions, fire detection and firefighting, smart appliances, and many others. As the costs of detectors comes down, the optics (lenses) often remain a cost-limiting component. It tends to be a bottleneck for emerging consumer products that require low-cost thermal imaging cameras.
“Traditional lenses for thermal imaging cameras are made from expensive materials such as germanium, high-grade silicon, and chalcogenide glass,” says Chalker. “These materials are very high performing, but their high prices, low-throughput manufacturing, and poor recyclability are limitations. In the case of germanium, global supplies are highly restricted because of its strategic use for defense. Lower-cost alternatives are required—especially for civilian applications.”
Polymers for thermal imaging lenses
Chalker’s lab was inspired by the creative work of Professor Jeff Pyun’s lab at the University of Arizona. “They previously demonstrated that sulfur-rich polymers made from ultralow-cost elemental sulfur have properties well suited to thermal imaging applications,” he explains. “Our team at Flinders developed several ways to make such polymers during the past decade, so we thought we could contribute to the thermal imaging applications of these materials. The specific polymer we made had been predicted to be useful for thermal imaging—on theoretical grounds—but no synthesis had been achieved due to complex chemistry and side reactions in previous approaches. Our lab loves a synthetic chemistry challenge, so we set out to solve the problem.”
Laser Focus World