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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.