Zoom microscope based micropositioning for MEMS sensor packaging system

This paper presents a zoom microscope based micropositioning system using feedback of multiple magnification images caught through a CMOS cameras mounted on an optical microscope. The requirement for real-time autofocusing for zoom microscope is proposed based on the analysis of zoom microscope model. In order to guarantee the accurate micropositioning of MEMS sensor packaging system, high magnification optical microscope is used. However, the small fleld-of-view of optical microscope essentially limits the workspace of the micromanipulator and the low depth-of-field makes it difficult to handle micro parts. To overcome these obstacles and increase the precision of micropositioning system, a zoom microscope is chosen to gain multiple magnification images. With low magnification, objects can be identified and located roughly. The precise position of objects can be calculated accurately with high magnification image. At last the autofocusing experiment and micro parts centering experiments are executed based on the micropositioning strategy. This micropositioning method, which base on zoom microscope, can also be used in micromanipulation and microassembly system.