Lower Material Costs
Thermoplastics are generally less expensive than glass. They are also made in very large volumes and are directly injected into the molding press in pelletized form. Unlike glass optics, thermoplastics are not pre-formed or shaped into a blank before injection molding.
Economies of Scale
In addition to being less expensive than glass, thermoplastics have a much shorter injection molding cycle time than the grinding and polishing techniques used to produce glass optics. Multi-cavity molds can also be built to produce multiple lenses during each molding cycle, which can further reduce costs for high-volume programs with commercial tolerances.
Aspheric surfaces can be added to optical systems to correct for geometric aberrations, such as spherical aberration, coma, astigmatism, and distortion. Complex shapes can be created at the optical mold insert and replicated many times during the injection molding process with excellent accuracy. Freeform optics are also becoming increasingly popular, particularly in AR/VR and HUD applications. The cost of producing freeform optics can be greatly reduced if the design can be optimized for injection molded plastics.
Combining Optical and Mechanical Features
Polymer optics can easily combine an optical surface with a mechanical mounting datum. This takes advantage of the manufacturing method of custom injection molding. By adding a mounting feature, such as a flange, tab, or other structure, the designer may be able to reduce the number of components in the final assembly and simplify the assembly process.