Molding and curing liquids can achieve rapid prototyping of new types of components.

Solid progress: The new way of manufacturing free-form optical components with components up to 200 mm can help such products more easily be used in a range of industrial applications.

Solid progress: components up to 200 mm

Due to its complex shape and lack of traditional symmetry, free-form surface components can perform new phase operations on incident light, which is beyond the possibilities of traditional optical surfaces, which opens up new application areas for glasses and other small-scale applications.

Over the years, people have recognized the potential impact of free-form optics. Jannick Roland of the Freeform Optical Center in the United States commented on Optics.org in 2013 that freeform optics was attractive in many ways, and the advancement of manufacturing technology at that time had exceeded the design mathematics of the project itself.

However, since then, it has been challenging to use mass production operations to manufacture larger free-form surface components, and newer 3D printing technologies have not yet guaranteed the surface quality required for effective free-form surface behavior.

Haifa Institute of Technology-A project of the Technion-Israel Institute of Technology has now developed an alternative manufacturing method that can make such components easier to manufacture and facilitate their use in the real world.

The breakthrough, published on Optica, involves shaping the volume of the liquid into the desired geometry and then curing the material. The method should allow researchers to quickly test free-form design concepts and allow moldless manufacturing on an industrial scale.

"Currently, optical engineers have to pay tens of thousands of dollars for specially designed free-form surface components, and then wait for several months to arrive," said Omer Luria of the Technion-Israel Institute of Technology. "Our technology is expected to fundamentally reduce the waiting time and cost of complex optical prototypes, which can greatly accelerate the development of new optical designs."

The new technology is based on a method of forming traditional optical elements from liquids, which was recently developed by Technion and involves injecting a curable optical fluid into a rigid boundary frame contained in an immiscible immersion liquid environment.

Applying this principle to the free-form surface geometry involves adjusting the shape of the boundary frame and an analysis model that relates the frame shape to the shape of the closed liquid interface that ultimately creates the free-form surface.

In practice, this involves injecting lens liquid into the support frame so that the lens liquid wets the inside of the frame and then relaxes into a stable structure. According to a paper published in this project, once the desired shape is achieved, the lens liquid can be cured by ultraviolet radiation or other methods.

After confirming that the technology can make simple spherical lenses, the project expanded their efforts to create free-form optical elements with a variety of geometric shapes, including toroidal and trilobal shapes, up to 200 mm in size.

"We have identified the infinitely possible optical terrain that can be manufactured using our method," said Mor Elgarisi of the Technion-Israel Institute of Technology. "This method can be used to manufacture components of any size, and because the surface of the liquid is naturally smooth, there is no need for polishing. This method is also applicable to any liquid that can be solidified, and has the advantage of not generating any waste."