Abstract In order to study the influence of air gap and focus position on the quality of ps-laser glass-to-glass welding we implemented a method of detecting the air gap between glass surfaces based on optical thin film interference. The method allows real-time optimization of the welding process. We measure the air gap between glass surfaces to be bonded and the laser focal position, which are set as the constraint conditions affecting the nonlinear self-focusing of the laser beam. The processing parameters of picosecond laser welding are determined and the welding strength and the morphology of bonded zone are detected and observed. Laser welding with good performance can be achieved with an air gap of 2 μm. SEM microscopy shows that the bonding region between two glass surfaces is very smooth in the vicinity of the tear-drop shaped cross-sectional structure of the welded glass. A tensile strength inspection fixture is designed, and we measured a tensile fracture strength of over 30 MPa for the welded glass. Through confocal microscope analysis, the width and depth of fracture morphology of welded samples are shown to change with air gap, which is consistent with the theoretical analysis.

中文翻译：

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间隙对使用皮秒激光的玻璃对玻璃焊接质量的影响

摘要 为了研究气隙和焦点位置对ps激光玻璃与玻璃焊接质量的影响，我们实施了一种基于光学薄膜干涉的玻璃表面气隙检测方法。该方法允许焊接过程的实时优化。我们测量要粘合的玻璃表面与激光焦点位置之间的气隙，将其设置为影响激光束非线性自聚焦的约束条件。确定了皮秒激光焊接的加工参数，检测并观察了焊接强度和结合区的形貌。气隙为 2 μm 即可实现性能良好的激光焊接。SEM显微镜显示，在焊接玻璃的泪珠状横截面结构附近，两个玻璃表面之间的结合区域非常光滑。设计了抗拉强度检测夹具，我们测得焊接玻璃的抗拉断裂强度超过30 MPa。通过共聚焦显微镜分析，焊接试样断口形貌的宽度和深度随气隙的变化而变化，与理论分析一致。