To produce the segments, Canon is drawing on its various optical technologies cultivated through the manufacture of lenses and mirrors, namely grinding and polishing technologies, aspherical surface
processing technologies, and measuring technologies.
Typical microstructures have triangular, pyramidal, spherical, and aspherical surfaces
with critical dimensions from several microns to several hundred microns, and their maximum local slope is up to 45-90[degrees] [8-10].
The avoidance of unwanted decentration is vital, and by combining minimum substance uncuts along with using aspherical surfaces
, optimum results can be obtained.
The lens unit consists of 7 elements in 6 groups with 3 aspherical lenses with 5 aspherical surfaces
Not only was mass-production impossible, but the fabrication of high-precision aspherical surfaces
was costly and difficult.