Vertically integrated transmissive microstructures for transforming light having Lambertian distribution

A method for manufacturing a light transmissive substrate for transforming a Lambertian light distribution, the method comprising:

• creating a plurality of first microstructures and a plurality of first valleys on a first side of a base film, each of the plurality of first microstructures having a first peak defining a first roof angle, and each of the plurality of first valleys being defined by an adjacent pair of first microstructures;
• disposing a filler material in the plurality of first valleys to establish a substantially planar surface spaced from and substantially parallel to the first side of the base film;
• and
• creating a plurality of second microstructures and a plurality of second valleys on the substantially planar surface of the filler material, each of the plurality of second microstructures having a second peak defining a second roof angle, and each of the plurality of second valleys being defined by an adjacent pair of second microstructures.