Liquid Mold, Droplets, Magnets – Lens Manufacturing

Researchers have developed a low-cost, easy way to make custom lenses that could help manufacturers avoid the expensive molds required for optical manufacturing. The researchers developed a liquid mold from droplets that they can manipulate with magnets to create lenses in a variety of shapes and sizes.

High-quality lenses are increasingly used in everything from cameras, to self-driving cars, and virtually all robotics, but the traditional molding and casting processes used in their manufacturing require sophisticated and expensive metal molds. So, manufacturers are mostly limited to mass-producing one kind of lens.

The researchers used 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 liquid 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.

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