Forming large pitch and depth patterns spontaneously based on a bottom–up approach is a challenging task but with great industrial value. It is possible to spontaneously form an uneven (concave–convex) patterns with submillimeter-to-millimeter-scale pitches and depths by the direct pattern exposure of a UV-curable oil-in-water (O/W) emulsion liquid film. UV irradiation generates a latent pattern of a cured particle aggregation in the liquid film, and an uneven structure is spontaneously formed during the subsequent drying process. This process does not require any printing and embossing plates or development process. In this report, we presented an example of unevenness formation with a maximum pattern depth of approximately 0.4 mm and a maximum pitch width of 5 mm. The patterns formed by this method have raised edges in the exposed areas and fogging in unexposed areas. The pattern shapes become conspicuous under overexposure conditions, but the formation mechanism has not yet been understood in detail and needs to be investigated. In this study, we focused on the exposure process and clarified the mechanism of pattern formation by analyzing the dynamics of emulsion droplets in the medium by an in situ microscopy observation method. As a result, we found that the fogging was mainly caused by light leakage from the exposed area, and the raised pattern edges were caused by droplets transported from the unexposed area to the exposed area. Furthermore, the convection caused by the heat generated from polymerization is a determining factor affecting all these phenomena. By controlling the pattern shape related to convection utilizing direct projection exposure, we showed an example of eliminating raised pattern edges with a height difference of approximately 0.1 mm. By devising and selecting exposure methods, we can expand the range of design applications such as interior decorative patterns.

基于自下而上的方法自发形成大节距和深度图案是一项具有挑战性的任务，但具有巨大的工业价值。通过UV固化水包油（O/W）乳化液膜的直接图案曝光，可以自发形成亚毫米至毫米级节距和深度的凹凸（凹凸）图案。紫外线照射在液膜中产生固化颗粒聚集体的潜在图案，并在随后的干燥过程中自发形成凹凸结构。此过程不需要任何印刷和压花板或显影过程。在本报告中，我们提出了一个最大图案深度约为 0.4 毫米、最大节距宽度为 5 毫米的凹凸形成示例。通过这种方法形成的图案在曝光区域具有凸起的边缘，而在未曝光区域具有雾化。图案形状在过度曝光条件下变得明显，但其形成机制尚未被详细了解，需要研究。在本研究中，我们通过原位显微镜观察方法分析介质中乳液液滴的动力学，重点关注曝光过程并阐明图案形成机制。结果，我们发现起雾主要是由曝光区域漏光引起的，凸起的图案边缘是由水滴从未曝光区域传输到曝光区域引起的。此外，聚合产生的热量引起的对流是影响所有这些现象的决定性因素。通过利用直接投影曝光控制与对流相关的图案形状，我们展示了消除高度差约为 0.1 mm 的凸起图案边缘的示例。通过设计和选择曝光方法，我们可以扩大室内装饰图案等设计应用的范围。