M.Sc.

Zontar, Daniel

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  • Publication
    Characterization of individualized assembly for BFL-compensated FAC on bottom tab modules
    ( 2018)
    Zontar, Daniel
    ;
    Müller, Tobias
    ;
    Sauer, Sebastian
    ;
    Baum, Christoph
    ;
    Brecher, Christian
    Uncertain glue gaps lead to challenging assembly tasks in respect to shrinkage control. With decreasing back-focal lengths (BFL) in collimators, the tolerance window for correct alignments decreases as well and forces manufactures to find novel approaches to realize the bonding process. We present performance characteristics of an automated assembly cell for individualized FAC on bottom tab modules. BFL-compensated collimators allow minimizing the critical adhesive gap between substrate and diode laser. This provides optimal control over shrinkage, as well as thermal aspects of the bonding properties. We will focus on the active alignment, which provides the individual focus distance, as well as the relative image processing necessary to assemble both components with ±1 µm precision. Our machine concept and measurement equipment is suitable as stand-alone process for optic manufacturers, as well as integrated part in the final application assembly. In last year’s publication (SPIE 10086), we presented the general concept and can now support our approach with more details from our operating data. With minimized adhesive gaps, the robustness of the proposed concept and a precise characterization of its process window is key, as minimal variations lead to rejects and cause high costs during the final application assembly. Besides classic properties, many more characteristics, e.g. smile behavior of the optic module, are potential optimization factors to increase beam quality. Characterization data from both optic and laser allow applying tolerance matching, where alignment is physically constraint. Performance wise, we will discuss the repeatability, achievable precision and the implications on process time.
  • Publication
    Curing-in-the-loop strategy for multidimensional-shrinkage compensation in active alignment FAC assembly
    ( 2018)
    Zontar, Daniel
    ;
    Müller, Tobias
    ;
    Sauer, Sebastian
    ;
    Baum, Christoph
    ;
    Brecher, Christian
    Tight tolerances for the final position and orientation of optical components are best controlled in automated and high volume production with statistical process control. Semi-automated and low-volume scenarios on the other hand are in need for a suitable approach, capable to react resiliently on remaining uncertainties of the bonding process. Active alignment has proven to lower the tolerances for finding the optimal position regarding the overall performance. We will present a novel shrinkage-compensation strategy, which extends the active control loop to integrate the curing process. We will discuss the adhesive properties necessary for the realization of our strategy and our measurement equipment used for the characterization of such properties. Besides a predicable shrinkage curve, the critical cross-linking level, until no further manipulation is possible, is a key factor. Furthermore, the machine concept, the curing capabilities and the active evaluation needs to follow special requirements. Since the shrinkage-behavior is highly sensitive to the amount of UV, the effective power on the adhesive needs to be controlled by optimizing the orientation of the light source. We integrated the UV-light in our micromanipulator in order to always ensure an optimal illumination In order to apply regression analysis for a multidimensional shrinkage model, misalignments in the selected degrees of freedom must be observable with sufficient precision. As validation of our strategy, we examine the collimation of a diode laser bar.
  • Publication
    Robust adhesive precision bonding of laser optics II
    ( 2017)
    Müller, Tobias
    ;
    Beleke, Andreas
    ;
    Haag, Sebastian
    ;
    Zontar, Daniel
    ;
    Sauer, Sebastian
    ;
    Baum, Christoph
    ;
    Brecher, Christian
    ;
    Wenzel, Christian
    Laser systems face massive economic challenges for cost effective, but yet ultraprecise assembly processes. Costs are mainly driven by the final assembly requirements of laser systems. Most challenging in this context is the robust process control of the UV-curing adhesive bonding process. The work presented aims for a significant reduction of the impact of shrinkage effects during curing and a resulting increase in assembly precision. Key approaches are integrated and characterized curing systems, ultraprecise dispensing processes and the automated characterization of adhesive shrinkage magnitude. These technologies allow for reproducible adhesive bonding processes in prototyping, job-shop assembly and automated assembly cells.