Embossing pattern shape characteristics in thin substrate microstructure formation via vertical vibration of resonant sessile droplets

초록

This paper introduces a novel micro-patterning technique that leverages the resonance of harmless water droplets, offering a distinctive alternative to traditional methods. An experimental setup was developed to validate this technique, where dynamic analyses were conducted to investigate the vibration characteristics of both the thin substrate and the sessile droplet. Modal analysis identified 16 resonance points, which were narrowed to three key frequencies through internal flow analysis. Voltage amplitude control was used to examine the effect on vertical velocity amplitude across different frequencies and their correlation with flow behavior. The study highlights three key patterning characteristics: internal flow formation, internal velocity behavior, and the resulting pattern shapes. As the frequency increases, the internal down flow becomes sharper, with the internal flow becoming more defined and the patterns narrower and clearer. Specifically, at 5.32 kHz, the flow is relatively blunt, producing broader patterns, while frequencies of 7.0 and 9.0 kHz result in more distinct patterns. The sharpness of the embossing patterns also increases with higher vibration frequencies, indicating a strong relationship between amplitude and pattern quality. The findings demonstrate that by optimizing both vibration input frequency and amplitude, this resonance-based micro-patterning technique enables precise control over embossing pattern characteristics. This approach has significant potential for advanced thinsubstrate manufacturing applications, offering a scalable, eco-friendly, and cost-effective alternative to conventional micro-patterning methods.

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