Layers Allow Artificial Lenses To Perform As Well As Human Eyes

By Nick Venable | Published

From bulletproof vests to Photoshopped images to cakes, the key to success for some products lies in the time-honored system of layering things. The Case Western Reserve University, Rose-Hulman Institute of Technology, U.S. Naval Research Laboratory, and PolymerPlus have all joined forces through years of research and development to create an artificial lens that is nearly identical to the lens in the human eye, and the method of fabrication is just as important as the materials themselves.

Yes, there is an acronym for the technology behind these polymer lenses, and it’s called GRIN: gradient refractive index optics. With a GRIN lens, as with the human eye, light is refracted by varying degrees as it passes through. That’s the opposite of how it works with traditional lenses, such as those found in a microscope or telescope, whose curved surface only refracts light one way or another. In the past scientists have focused on other aspects of optics to bend light to various degrees, since the technology didn’t exist to replicate the gradual evolution of refraction.

And so the layering and stacking began. The team built a lens out of a staggering amount of nanoscaled layers, each designed with slightly different optical properties, which allows for variations in the refractive index. A 4,000-layer film is coextruded, giving it the unique refractive index, and then 200 layers of the film are stacked to create the lens, now 800,000 nanolayers thick. The technique is optimal for the ability to stack any combination of layers to fit researchers’ needs. These layers are so small that you can’t see them, but they at least give you the ability to see it, even though you can’t. That’s progress!

It’s already thought that these new, soon to be commercialized lenses will replace current generation intraocular replacement lenses, such as those for cataracts or contacts, ridding users of optical aberrations experienced in the single-refractive lenses. GRIN’s lack of complicated components bears well for other areas as well, such as consumer vision products and aerial-based military surveillance products.