Researchers at Washington State University, in conjunction with Ohio State University, have developed a novel technique for manufacturing lenses. The technique is low-cost and works by using magnets to manipulate droplets, eventually creating lenses in various shapes and sizes. Their work was recently featured in the journal Applied Physics Letters.
“We brought the concept of interfacial tension to the field of optics by introducing an innovative controllable liquid mold,” says Lei Li, project lead and assistant professor in the School of Mechanical and Materials Engineering at Washington State University. “This novel process allowed us to regulate the shape of a magnetic drop and to create lenses without having to fabricate expensive molds.”
From the Washington State University article: "They first tried to make their own lenses using 3D printing but found it difficult to control the lens shape. They then came up with the idea of using magnets and the surface tension of liquids to literally create free-flowing molds.
They placed tiny, magnetic iron particles into liquid droplets and built a device to surround the droplets with magnets. They then poured the plastic material used in lenses over the droplet. As they applied a magnetic field, the droplet took on a conical lens shape – creating a mold for the plastic lens material. Once they cured the plastic, it hardened and had the same optical properties and imaging quality as a commercially purchased lens. The liquid droplet remains separate and can be re-used.
The magnets can be moved to change the magnetic field, the shape of the mold, and the resulting lens. The researchers also used bigger or smaller droplets to create lenses of varying sizes."
Read more about the novel lens manufacturing technique using magnets at Washington State University.