Process Monitoring in Automatic Assembly of Minilenses With Fiberscopes

In this paper, we present experimental results of process monitoring and process control in automatic assembly of minilenses in front of a miniature flexible fiberscope. For the purpose of process visualization and process control, an LED light source, a grating and a micrometer screw are compacted together in a vacuum gripper. A positioning system, a fiber chuck, a mimilens magazine and a fiberscope have been installed in the system and an image processing algorithm for process control has been developed. The optical design and assembly process are presented here in details. The projection of an illuminated grating through the minilens on the fiberscope is used to position the minilens automatically by an image processing unit and the motion system. The position system has a minimum step size of 5 μm in translation and 0.01° by rotation. The repeatability of the translation stages is about ±2.5 μm. It is shown from the experimental results that the tilt axial angle between the optical axis of the minilens and the geometrical axis of the fiberscope is less than 4°.