| Modern manufacturing incorporates fabrication constraints and quality control into the initial product design to create competitive, cost-effective products. This research offers a design-for-manufacture approach to gradient-index lens production. Fabrication parameters are coupled to a lens design program to eliminate the traditional trial-and-error manufacturing process. The new approach allows a lens designer to design a gradient-index optical system in terms of the actual fabrication parameters and then provides a set of experimental specifications to the materials scientist. The result is a more efficient and cost-effective manufacturing process for gradient-index optical systems.; Traditional gradient-index design methods were developed before many of the current gradient-index materials were available and are therefore unrelated to the material fabrication parameters. For example, the index of refraction profile is typically expressed by a polynomial expansion in optical design. Once a lens is designed with this representation, the manufacturer must guess at fabrication parameters such as time and temperature to obtain the required {dollar}Delta{dollar}n, depth, and profile shape. As a result, the design-to-manufacture process is slow and iterative.; Therefore, a more efficient design-for-manufacture approach is offered by this research. First, a mathematical model for gradient-index fabrication by ion exchange is developed using Fickian diffusion theory. Second, an experimental procedure is developed to test this model against experimental results for several different diffusion times and temperatures in both axial and radial sample geometries. In particular, empirical diffusion models are developed for Li{dollar}sp+{dollar} for Na{dollar}sp+{dollar} and Na{dollar}sp+{dollar} for Li{dollar}sp+{dollar} ion exchange in alumina silicate glasses, alumina borate glasses, and titania silicate glasses. Third, the model is integrated with a lens design program to allow optimization on diffusion parameters and several sample designs are presented which compare the old design procedure with this new method of design. Thus, with the completion of this research, a lens designer can now choose from a realistic set of gradient-index glasses and, in turn, generate a complete set of experimental specifications for the production of the gradient. |
