Proper optical design, manufacturing and coating make plastic a low-cost alternative material to glass for precision optics.
David J. Butler, Polaroid Corp., Norwood, Mass.
Injection-molded plastic optics with precision requirements were most likely first produced in high volume by Eastman Kodak Co. during the 1960s. The lenses were spherical and crude by today's standards. In the late 1960s, Polaroid Corp. and others developed advanced measuring capabilities and precision lathes that produced precision aspheric surfaces.
Since the early days, manufacturing methods have improved dramatically, and the number of participating companies has increased. In some areas, plastic lenses have surface quality comparable to glass analogs. For example, compact disc lens manufacturers consistently make lenses to subdiffraction-limited tolerances.
Improvements in the quality of plastic optics have allowed them to proliferate into many areas dominated by glass optics. The next large applications will include telecommunications, high-resolution microdisplay applications and longer-term high-speed computers.
With the technology available today, plastic optics can be both a low-cost alternative to glass and an option that provides more degrees of freedom for product and optical design.