Automated assembly of microoptical components

In the field of microsystem technologies one future trend is recognized. Manufacturing microsystems monolithically is becoming less reasonable and practicable with increasing applications and complexity. Assembly processes will be needed for the majority of microsystems due to difficulties arising in manufacturing complex structures out of one piece, the need for components to be manufactured by different processes, or simply to connect the microsystem with the macroscopic environment. Additionally, high production output at competitive costs is attainable only by replacing manual assembly with new automatic handling, positioning and joining technologies. To assist in development of microassembly processes, techniques from macroassembly technology may be transferred. Especially in microoptics existing know-how from macroscopic lens-assemblies might be transferred. The microsystem presented in this paper involves a wide range of requirements needing to be satisfied frequently in microsystem assembly. It represents a microoptical beam forming system consisting of one SELFOC- and two GRIN-microlenses joined by adhesive bonding, fu;ed in a protection-mount, which serves additionally as a coupling unit of a multimode fibre, and finally adjusted to a laser diode at a defined distance according to an optical design. Besides complications due to the sensitive optical surfaces and the small and varying geometries of the system components, there is the additional requirement of high accuracies, of 0.1 to 2 mu m and down to 1 arcsec, needed to realize the optical function of the microsystem. The assembly system, based on a six-axis-precision robot accurate to less than 1 mu m, consists of a modular designed tool changing system, specially-adapted, self-adjusting grippers, several sensors to monitor positioning, dosage devices to dispense measured quantities of adhesive, in the range of nanolitres, and a specially designed assembly platform to clamp microparts of different geometries.