Research Progress on Mechanisms for Controlling Coating Uniformity on the Outer Layer of Glass and Process Optimization

WANG Yanxin; HUANG Huixuan; LI Xu; LI Yan; YUAN Yingcai; REN Zheng

doi:10.19554/j.cnki.1001-3563.2026.19.025

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Packaging Engineering ›› 2026, Vol. 47 ›› Issue (19) : 247-259. DOI: 10.19554/j.cnki.1001-3563.2026.19.025

Equipment Protection

Research Progress on Mechanisms for Controlling Coating Uniformity on the Outer Layer of Glass and Process Optimization

WANG Yanxin¹, HUANG Huixuan¹, LI Xu², LI Yan¹, YUAN Yingcai¹, REN Zheng^1,*

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Abstract

The work aims to systematically review the mechanisms underlying the uniformity of outer-layer coating on glass, elucidate the fluid dynamic nature of typical defects, and provide theoretical guidance for process optimization. Focusing on five typical outer-layer coating processes, including flow coating, spray coating, dip coating, squeegee coating, and slot coating, the multiscale mechanisms by which rheological and physicochemical properties, such as coating viscosity, surface tension, yield stress, curing behavior, and solvent evaporation, affected liquid film stability were thoroughly analyzed; key quality evaluation and defect characterization methods, including microscopic observations of cross sections, non-contact laser thickness measurement, 3D morphological reconstruction, optical property testing, and tape peeling were systematically summarized; key fluid dynamics dimensionless numbers, such as the Reynolds number (R_e), capillary number (C_a), Weber number (W_e), and Bond number (B_o) were introduced to explore strategies for the synergistic optimization of process parameters based on the theory of multidimensional precision coating windows. The study found that sagging was primarily controlled by the combined effects of the Bond number and the capillary number; capillary ridge formation was closely related to dynamic contact line migration and surface tension gradients; and air entrapment exhibited critical instability conditions dominated by the capillary number. Appropriately matching the rheological properties of the coating with process parameters could effectively broaden the stable coating window. The established "rheological properties, dynamic defects and process window" theoretical framework provides a systematic theoretical reference and engineering design basis for precise uniformity control in large-area glass outer-layer coating, suppression of multidimensional interfacial defects, and high-quality smart manufacturing of high-performance functional devices.

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outer-layer coating / coating uniformity / rheological behavior / coating window / process optimization

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WANG Yanxin, HUANG Huixuan, LI Xu, LI Yan, YUAN Yingcai, REN Zheng. Research Progress on Mechanisms for Controlling Coating Uniformity on the Outer Layer of Glass and Process Optimization[J]. Packaging Engineering. 2026, 47(19): 247-259 https://doi.org/10.19554/j.cnki.1001-3563.2026.19.025

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