SBIR Phase I: Exposure Controlled Projection Lithography for Fabrication of Physical Shaped GRIN Optics

This Small Business Innovation Research Phase I project aims to create a unique maskless lithography technology called "Exposure Controlled Projection Lithography" (ECPL), to enable manufacturing of gradient index (GRIN) optical components with controlled physical aspheric shapes. ECPL is an advanced additive stereolithography fabrication technology which will reduce the manufacturing cost and time, and provide high flexibility over the shape and refractive index distribution compared to existing manufacturing processes. A key advantage of the ECPL approach is that smooth optical surfaces can be fabricated, without the stair-stepping caused by typical layer-by-layer fabrication methods, on flat as well as curved substrates. The primary focus of this proposal is to further ECPL fabrication capability to include three-dimensional lenses that possess multi-dimensional varying GRIN profiles. The primary intellectual merit of this project lies in furthering the scientific understanding of advanced photopolymerization in stereolithography processes, and developing high fidelity multi-directional control over these physical behaviors. Key intellectual advancements include constructing high-fidelity models of resin response, advancing the development of an interferometric real-time monitoring system, and improving process planning and control algorithms. This effort will result in an intelligent, flexible aspheric GRIN microlens fabrication process. The broader impact/commercial potential of this project is to develop an enabling technology for a wide range of research and commercial products, and represents a key advancement in an industry trend towards single-step fabrication at low cost, high throughput and yield, and without re-tooling or equipment downtime. The processes and control algorithms proposed to be developed have potential to facilitate technologies throughout the Opto-Electro-Mechanical systems' industry, including numerous biomedical and bio-inspired design applications, micro-fabrication, holographic data storage, nano-scale manufacture, micro-scale quality assurance and non-destructive testing, surveillance systems, and health care, amongst many others. The broad appeal of ECPL-like processes is simple: utilizing dynamically controllable micro-fabrication techniques to create microstructures that vary three-dimensionally in both shape and material properties without the need for pre-formed masks, molds, or tooling greatly improves the flexibility of micro-manufacturing systems while keeping production costs to an absolute minimum. ECPL technology will enable research of bio-inspired optical designs, including the GRIN contact lens for human vision correction and the wide field of view (fly's eye) concept. The real-time monitoring system ECPL supports nearly any stereolithographic process, and since virtually all raw materials are converted into final product, provides an additive benefit of environmentally friendly part production.