System and method for manufacturing gradient material structures, such as gradient refractive index materials

A system for manufacturing a gradient material structure, the system comprising:

• a proportioner feedblock section having a first flow inlet for receiving a first polymer material in melted form, a second flow inlet for receiving a second polymer material in melted form, and one or more proportioner channels, each said proportioner channel having
• (a) a proportioner outlet;
• (b) a first polymer conduit in fluid communication between the first flow inlet and the proportioner outlet;
• and
• (c) a second polymer conduit in fluid communication between the second flow inlet and the proportioner outlet;
• and
• a mixer feedblock section having a plurality of mixer channels extending therethrough, each of the mixer channels being in fluid communication with the proportioner outlet of a corresponding said proportioner channel;
• wherein
• (a) each mixer channel is configured to simultaneously receive from the corresponding proportioner channel the first polymer material at a first volume flow rate and the second polymer material at a second volume flow rate, the ratio between the first and second volume flow rates defining at least in part a polymer transfer ratio for the respective mixer channel, and
• (b) the polymer transfer ratios differ between two or more of the mixer channels.