Historically, products that use lenses either produce sharp, realistic images or they have a large field of vision, but a UW-Madison research team has designed a way to achieve both—all in a very tiny package.
The team, led by UW-Madison professor of electrical and computer engineering Hongrui Jiang, developed the first flexible Fresnel zone plate microlenses, according to a university release. The lenses could lead to much smaller security cameras and surgical scopes that capture much larger images.
Smaller than the head of a pin, Jiang’s microlenses are embedded in a flexible plastic that can be rolled into a cylinder to capture panoramic images up to a 170-degree field of view. The team drew inspiration for the lens arrangement from multifaceted insect eyes.
"We got the idea from compound eyes," Jiang said in the release. "We know that multiple lenses on a domed structure give a large field of view."
Fresnel zone plates, named after a 19th-century engineer, allow Jiang and his team to freely change the lens shape and configuration.
The researchers used these zone plates and new materials to create the microlenses, which produce clearer images and are more flexible than any other lens.
Rather than refraction, the conventional method of passing light through substances, the new Fresnel plates focus by diffraction, which bends light as it moves over a barrier. Pairing this method with black silicon, which does not reflect or transmit any light, resulted in more crisp images than previous attempts.