From Spheric to Aspheric Solid Polymer Lenses: A Review
Figure 1
Schematic diagram of the self-assembly mechanism of the lens: (a) fixed focal length and (b) variable focal length methods. Both types of design employ hydrophilic/hydrophobic interface characteristics to form areas with different surface tension. When lens material is applied, the material will tend to remain in hydrophilic zones with high surface free energy. The goal of the variable focal length process is to resolve the problem of excessively small numerical aperture (NA) that occurs when the conventional self-alignment method is employed.
