Micro-optical components, e.g. micro-aspheres, micro-optical freeform surfaces or diffractive optical elements, are key enabling components in miniaturized imaging and sensing devices.
Wafer level replication methods can be used in order to ensure a cost-effective manufacturing of these elements in batch processes. Therefore, a master-wafer is required. Typical methods for the generation of master-wafers, e.g. grayscale photolithography, electron-beam lithography, ultraprecision-micromachining or two-photon-lithography often permit the manufacturing of small-sized single masters only.
The step-and-repeat replication process allows the transition from the single master to a wafer-master. Alternatively, micro-optical elements can be replicated directly on glass substrates with lithographically patterned diaphragms in order to produce prototypes or a small batch series.