Methods and apparatuses for casting optical polymer films

A system for forming an optical film for an eyepiece, the system comprising:

• a first mold portion having a first mold surface;
• a second mold portion having a second mold surface, wherein the first mold surface is opposite the second mold surface;
• a dispenser;
• a measurement apparatus comprising a plurality of sensors;
• one or more actuators coupled to at least one of the first mold portion or the second mold portion;
• and
• a curing apparatus,
• wherein the dispenser is configured, during operation of the system, to dispense a curable material into a space between the first mold surface and the second mold surface,
• wherein the control module is configured, during operation of the system, to cause the system to measure a position of the first mold surface relative to the second mold surface, wherein measuring the position of the first mold surface relative to the second mold surface comprises:
• determining a first relative distance along a first measurement axis between a first point on a planar portion of the first mold surface and a first point on a planar portion of the second mold surface using a first of the sensors,
• determining a second relative distance along a second measurement axis between a second point on the planar portion of the first mold surface and a second point on the planar portion of the second mold surface using a second of the sensors, and
• determining a third relative distance along a third measurement axis between a third point on the planar portion of the first mold surface and a third point on the planar portion of the second mold surface using a third of the sensors,
• wherein the first, second, and third measurement axes are parallel to each other, the first, second, and third points define corresponding triangles on the first and second mold surfaces, respectively, and the space between the first and second mold surfaces is located within the triangles;
• determining, based on the first relative distance along a first measurement axis, the second relative distance along a second measurement axis, and the third relative distance along a third measurement axis:
• coordinates (x1,y1,z1) of the first point on the planar portion of the first mold surface or the first point on the planar portion of the second mold surface with respect to a Cartesian coordinate system,
• coordinates (x2,y2,z2) of the second point on the planar portion of the first mold surface or the second point on the planar portion of the second mold surface with respect to the Cartesian coordinate system,
• coordinates (x3,y3,z3) of the third point on the planar portion of the first mold surface or the third point on the planar portion of the second mold surface with respect to the Cartesian coordinate system, and
• wherein the one or more adjustments are determined according to a relationship
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• =
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• ,
• wherein Z corresponds to the translation of at least one of the first mold surface or the second mold surface along an axis of translation,
• wherein Rx corresponds to the rotation of at least one of the first mold surface or the second mold surface about a first axis of rotation, and
• wherein Ry corresponds to the rotation of at least one of the first mold surface or the second mold surface about a second axis of rotation;
• wherein the one or more actuators are configured, during operation of the system, to adjust the position of the first mold surface relative to the second mold surface based on the measured position;
• and
• wherein the curing apparatus is configured, during operation of the system, to cure the curable material in the space to form the optical film.