Automated assembly of fast-axis collimation (FAC) lenses for diode laser bar modules

Abstract

Laser diodes and diode laser bars are key components in high power semiconductor lasers and solid state laser systems. During manufacture, the assembly of the fast axis collimation (FAC) lens is a crucial step. The goal of our activities is to design an automated assembly system for high volume production. In this paper the results of an intermediate milestone will be reported: a demonstration system was designed, realized and tested to prove the feasibility of all of the system components and process features. The demonstration system consists of a high precision handling system, metrology for process feedback, a powerful digital image processing system and tooling for glue dispensing, UV curing and laser operation. The system components as well as their interaction with each other were tested in an experimental system in order to glean design knowledge for the fully automated assembly system. The adjustment of the FAC lens is performed by a series of predefined steps monitored by two cameras concurrently imaging the far field and the near field intensity distributions. Feedback from these cameras processed by a powerful and efficient image processing algorithm control a five axis precision motion system to optimize the fast axis collimation of the laser beam. Automated cementing of the FAC to the diode bar completes the process. The presentation will show the system concept, the algorithm of the adjustment as well as experimental results. A critical discussion of the results will close the talk

Robust Adhesive Precision Bonding in Automated Assembly Cells

“…Assembly costs are driven mainly by the demanding requirements regarding alignment and adhesive bonding in all spatial dimensions. Extensive research efforts are being made in matters of novel bonding methods, whilst the challenges of the state-of the art UV-curing adhesive bonding still provide opportunities for improvement as identified in several recent research projects and contributions ( [1], [2], [3], [4], [5], [6], [7]). …”

Engineering of automated assembly of beam-shaping optics

“…In [1] and [2] automation concepts have been presented for fast-axis collimators putting the focus on the feasibility of automated assembly and the technical realization. In [1] the authors describe the image-based evaluation of the collimated beam by introducing one-dimensional intensity profiles in the near-field and in the far-field for the automated alignment of fast-axis collimation lenses for laser diode bars.…”

Chain of refined perception in self-optimizing assembly of micro-optical systems

“…In the case of collimation optics, an optical measurement setup and a CCD chip are used for determination of the current state of alignment. Alignment algorithms have been and currently are subject to recent research activities Haag and Härer, 2012;Pierer et al, 2011;Miesner et al, 2009). …”

“…Due to its complexity, industrial assembly of high-technology diode laser systems is dominated by manual processes, which determine the majority of overall production costs. The feasibility of automation of such assembly tasks has been proven in several research projects Haag and Härer, 2012;Loosen et al, 2011;Pierer et al, 2011;Miesner et al, 2009) as well as in a few industrial applications. A breakthrough of automation in this field has not yet been achieved.…”