It’s not the size that matters in lenses that were created by engineers from the University of Wisconsin-Madison. The first-ever flexible Fresnel zone plate microlenses offer a wide field of view. The development of these lenses has the potential to allow items from security cameras to surgical scopes to capture images in small spaces, but from a broader perspective.
The advances made in this technology centers on the method used to create these lenses, which are the size of a grain of salt. The lenses were embedded into a flexible plastic polymer. To test the technology, lenses were embedded into cylindrical structures and the lenses, no larger than the head of a pin, were able to capture an “almost complete panorama” and capture images from a 170-degree field of view.
Multiple lenses on a domed structure offer a large field of view and with the advent of these new Fresnel micro lenses, it’s anticipated that there will be improvements in surgical scopes and security cameras in both the field of view and in the miniaturization of the instruments and cameras.
The lenses mimic “insect eyes” but capture a larger field of view and have the ability to flex and contort. Each of the tiny lenses sits within flexible plastic polymer and that allows the researchers to easily configure and shape the lens array. The lenses have been manipulated in this manner, rather than in conventional optics used for focus because they incorporated the Fresnel zone plates. In most instances, the researchers noted, flexible structures are incompatible with optics, but in the newly developed technology the lenses are both small and the optical properties are fine.
In a typical lens, the material is stiff and translucent and are machined into either convex or concave shapes. Traditional lenses capture images by changing the trajectory of incoming light into a single focal point by using refraction. The Fresnel zone plate lenses focus the light through diffraction – constructive and destructive interference. The newly developed lenses look like a series of rings on the surface of still water as they emanate from a single start point and mimic a bullseye pattern. The distance between the rings are what determines the optical properties of the lens and this allows the researchers to “tune” the optical properties of a single lens without disrupting the other lens properties.
In past attempts in making Fresnel zone lenses the images were not clear and researchers found there had to be dramatic delineation between dark and light areas to capture clear images.
The researchers are currently looking for ways to implement the microlenses into real-world settings.
Universe Kogaku designs and manufactures optical lenses for industrial, medical, high tech and electronic applications. Standard and custom lens assemblies for scanners, CCTV, CCD/CMOS, medical imaging, surveillance systems, machine vision and night vision systems.