3D printing creates new possibilities in sensor technology
3D printing, in which material is added layer by layer, is able to create complex geometric shapes quickly and efficiently. One field of technology where this industrial method holds huge potential is optical sensors. “Optical sensors are everywhere in today’s world,” explains 3DPRINTEDOPTICS project coordinator Harald Giessen, professor of Experimental Physics at the University of Stuttgart in Germany. “They can be found in smartphone cameras, cars and medical imaging devices such as endoscopes.” For all these applications however, size remains a limiting factor. Manufacturing effective micro-optical sensors significantly smaller than 1 mm has proven hard to achieve, without sacrificing performance. This is where 3D printing comes in. “We invented 3D printing for really small micro- and nano-optics during a previous EU-funded project,” adds Giessen. “It worked really nicely. When our results started to attract attention, we began thinking about whether we could bring this technology to industry, and launch a start-up.” This was the inspiration behind the 3DPRINTEDOPTICS project. Giessen and his team focused on perfecting their production process of creating flexible micro-optic prototypes of less than a millimetre in size. This is done by precisely directing a laser to shape tiny complex structures. The finished micro-optics, which can be many times smaller than the head of a matchstick, can then be placed on the tip of an optical fibre or image sensor.
Identifying industry demand
A key potential end user is medical equipment manufacturers. “We are actually able to print micro-optics directly onto optical fibres,” says Giessen. “This is ideal for medical imaging. These optical fibres can be then sent through tiny vessels. Dentists could use these micro-optics to examine root canals, for example.” Other potential medical uses include taking images inside the womb or examining the internal structure of vessels, the inner ear or intestines as non-invasively as possible. The potential of micro-optics is not just limited to the field of medical devices. Next-generation cars have around 60 optical sensors, and this number is only set to increase. “It is likely that rear mirrors will eventually be replaced with cameras, while self-driving cars need cameras capable of check the surrounding environment,” he adds. “At the same time, you don’t want your new car covered with all kinds of sensors. The benefit of these micro-optics is that you can place lots of them, each with a different focus, on one chip. Some might have strongly curved surfaces, ideal for capturing surrounding views, for example.”
Next-generation optics
The success of the project has enabled Giessen and his colleagues to launch a spin-off company called PrintOptics GmbH. At present, the start-up is developing prototype products for medical imaging and automotive companies, in Europe and abroad. “These companies are currently running tests,” he notes. “They are examining issues such as efficacy, reuse and, in the case of medical imaging, safety issues.” Giessen sees the start-up as eventually being able to offer services ranging from consulting through to bespoke design and manufacturing prototypes and small series. The company is already thinking of expanding to meet potential demand. Looking further into the future, Giessen sees opportunities for micro-optics everywhere. “Next-generation optics could include tiny optics in your glasses, offering augmented and virtual reality. This would aid in finding directions or enable you to conduct conference calls, seeing the other partners holographically,” he says.
Keywords
3DPRINTEDOPTICS, 3D, optical, sensors, micro-optical, laser, medical, imaging