Laser Catapulting To Create Microlens Arrays

A growing number of applications, including smartphone cameras, depend on microlens arrays to boost performance, for example by compensating for the “dead space” around detector pixels. However, although micro-optics are commercially available, they can be prohibitively expensive to fabricate and hard to add to existing devices. Even with traditional microlens fabrication methods (see single point diamond turning) such as photolithography, it is difficult to integrate lenses or to make very densely packed microlens arrays. A newly developed technology called laser catapulting could make it much easier and less expensive to fabricate micro-optics and tailor their properties such as shape or refractive power.

The new laser-additive method creates microlenses each using a single laser pulse and allows microlenses and microlens arrays to be fabricated directly on cameras or solar cells if desired.

A laser pulse removes and catapults a microdisk from a thin polymeric film and drops it onto a defined region of interest. The polymer in the microdisk is then heated so it can thermally reflow, allowing capillary forces to shape the microdisk into a round lens. Changing the shape of the laser beam allows the fabrication of microlenses with different focusing properties or shapes, such as rectangular, triangular, or circular. The method could be used to reproducibly produce microlenses with radii between 50 and 250 μm and very high smoothness.

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