Patent ID: 6845634
Filing Date: 2005-01-25
Classification: C03B,C03C

Abstract:
1. A method for making a GRIN lens comprising the steps of: (a) preparing a cylindrical preform consisting essentially of silicon in the range of 15 to 25 atomic %, oxygen in the range of 50 to 65 atomic %, boron in the range of 0.2 to 4.5 atomic %, zinc in the range of 0 to 8 atomic %, potassium in the range of 0 to 1.5 atomic %, sodium in the range of 2 to 12 atomic %, and thallium in the range of 2 to 13.5 atomic %; (b) annealing said cylindrical preform to eliminate residual stresses; (c) removing a contaminant layer from said cylindrical preform, said cylindrical preform thereafter extruded into a glass rod; (d) annealing said glass rod during an ion exchange process within a static bath composed of alkali salt; and (e) milling said glass rod within an acid bath to refine diameter of said glass rod.