Modeling of light field effect in deep vat polymerization for grayscale lithography application

Mohammad Mahdi Emami, David W. Rosen

Research output: Contribution to journalArticlepeer-review

17 Citations (SciVal)


The application of digital micromirror device (DMD) for maskless lithography and vat photopolymerization in the micro-fabrication processes is increasing. Therefore, a high-fidelity model that describes the DMD's light propagation in a medium is required. To achieve this goal, we initially measured the light field and the intensity evolution beyond its focal plane for a single pixel and multi-pixels pattern. Then, the divergent angle of the field has been obtained. In order to identify the effect of a light field in a vat polymerization performance, two scenarios were investigated: with and without light field effect (LFE). The measured light field data, as well as a uniform light field (without LFE), are fed to a previously developed FEM Multiphysics simulation software as an input. The simulation consists of photochemical kinetic reactions and light attenuation. For each scenario, the output was captured to generate distribution contours that represent the variations in the degree of conversion in the medium. The influence of LFE was investigated for two separate regions: the center and sidewall of the exposed pattern. The evolution of sidewalls angle vs. curing depth was experimentally validated.

Original languageEnglish
Article number101595
JournalAdditive Manufacturing
Early online date11 Sept 2020
Publication statusPublished - 31 Dec 2020


  • DMD light field
  • Frontal photopolymerizationion
  • Grayscale lithography
  • Light propagation

ASJC Scopus subject areas

  • Biomedical Engineering
  • Materials Science(all)
  • Engineering (miscellaneous)
  • Industrial and Manufacturing Engineering


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