Nanocoining: High speed high throughput imprinting of micro and nano-scale features on moving substrates


Background: The application and advantages of micro and nano structures in non-reflective surfaces is conspicuous from their usage in a broad spectrum of technological domains. Applications ranging from LEDs semiconductors and flexible electronics to energy efficient glass lighting products and solar photovoltaic cells benefit from various surface modifying technologies enabled by nanofabrication and nanomanufacturing. Additionally micro structured surfaces are often used to engineer mechanical applications involving adhesives moisteners and friction coefficients. Unfortunately however despite significant engineering applications current techniques are not feasible to cater to the high demand due to of their long manufacturing times. Photolithography methods are popular and can produce a limited area of high quality features but involve a large number of manufacturing steps including spin coating baking etching development etc. as well as sensitive chemical formulations and process environments. Technology Description: Nanocoining is a robust new process developed at the Precision Engineering Center (PEC) in NC State University. This new technology enables transferring nanofeatures from a small die directly to a work piece or indirectly through an intermediate mold at high speed. Nanocoining can be used to create high-quality indents on a metal mold which can be replicated for larger blocks. The features created on these metallic mold surfaces are considerably more robust than the nanostructures created from polymers. This technique can be used to produce tapered optical features between two given surfaces by creating a gradual change in the refractive index between them. A tapered index change enables reduced Fresnel reflection thereby producing the desired anti-reflective properties. This type of surface modification can also be applied rapidly to large area photovoltaics enhancing their ability to perform over multiple wavelengths of light and large viewing angles. Applications: 1) LEDs 2) Semiconductors and flexible electronics 3) Energy efficient glass lighting products 4) Solar photovoltaic cells


1) Create optical structures with tapered refractive index 2) Ability to create high quality nanostructured surfaces with high throughput 3) Avoids smearing by using an elliptical tool path 4) Uniform indentation depth

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