Laser beam micro forming as a new adjustment technology using dedicated actuator structures

Abstract

The increasing demands in MEMS fabrication in the past led to new requirements in production technology for these devices. Especially the packaging and assembly of optical devices like high power diode lasers require high accuracy in positioning and high reproducibility in combination with low production costs. Conventional assembly technology and mechanical adjustment methods are time consuming and exspensive. Therefore a need of new assembly procedures arose. Each component of the system has to be positioned and fixed. The equipment for manipulating is very expensive. Also adjustment of the parts after joining requires additional mechanical devices that need to be accessible after joining. The decreasing dimensions of the microsystems cause problems in assembly and increase dramatically the tolerance conditions The laser beam micro forming as a non-contact tool offers the possibility of active adjusment after the assembly is completed. This paper describes this new technology pointing out the used mechanisms of laser induces deformation: From the basic mechanisms dedicated structures are derived to achieve the desired degrees of freedom for the adjustment process. Based on the upsetting mechanism the positioning of a cylindrical lens in front of a high power diode laser is shown. The adjustment in two degrees of freedom can be realized by irradiating the actuating structure from one direction. The achieved accuracy is in the micron range. The knowledge transfer to a tube-like actuator will be demonstrated. The tilting of a mirror in two rotational movements will be shown. The results to be presented have partially been achieved within the Collaborative Research Center (SFB) 440 "Assembly of Hybrid Microsystems" which was financially supported by the Deutsche Forschungsgemeinschaft DFG.