STTR Phase I: Predictive Molding of Precision Glass Optics

This Small Business Technology Transfer Phase I project aim to develop an economical method for production of aspheric glass optical elements. Production of aspheric glass optics by compression molding is currently not widely practiced. One of the primary reasons for this is that no method exists to determine the required mold geometry to produce a desired optic geometry. The only available method for producing molds is a time-consuming and expensive trial and error process whereby precision molds are fabricated, optics are molded and inspected, and errors in the resulting optic are used to create new molds with slightly different geometry. This process continues iteratively for many cycles until a satisfactory mold geometry is obtained; adding significantly to the cost of the process and necessitating long lead times. This project will develop physics based computational models of the glass molding process that accurately predict the shape of the optic from knowledge of the mold geometry, the material properties of the glass, and the molding parameters. The models will be developed through systematic characterization of the properties of glasses at high temperatures, incorporation of the the viscoelastic response of the glass with thermal expansions and elastic deflections of the mold and glass into computational models of the process. The broader (commercial) impacts from this project will be many consumer devices, such as DVD players, digital cameras, etc., incorporate aspherical optical elements produced by injection molding of optical polymers. This is currently the only technology capable of producing the required optics at acceptable cost. However, there is increasing pressure to move to glass optics due to their superior optical properties, which will result in superior device performance. While glass molding is widely practiced for production of containers and other low tolerance items, it is not currently widely used for the production of precision optics. The computational tools developed in this proposal will eliminate the current need for production of many expensive trial mold geometries before discovering the proper mold geometry and processing parameters required to produce in-tolerance optics. It will enable molds for glass optics to be produced in a deterministic manner and remove one of the largest technological barriers to adoption of this technology. This will enable opto-electronic products with superior capabilities compared to those available today. The methods developed here will have broader application to other precision molding and casting processes.