Proceedings of the Korean Society for Technology of Plasticity Conference (한국소성가공학회:학술대회논문집)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Formation of Microlens Array via a Modified LIGA Process: Molding and Modeling

변형 LIGA 공정을 이용한 마이크로 렌즈 어레이 개발: 몰딩 및 모델링

  • Kim, D. S. (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • Lee, H. S. (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • S. S. Yang (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • Lee, B.K. (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • Lee, S.K. (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • T. H. Kwon (Dept. of Mechanical Engineering, Pohang University of Science and Technology) ;
  • Lee, S. S. (Dept. of Mechanical Engineering, Pohang University of Science and Technology)
  • Published : 2003.05.01
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Abstract

Microlens arrays were fabricated using a novel fabrication technology based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep X-rays and subsequent thermal treatment. X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. A new physical modeling and analyses for microlens formation were presented according to experimental procedure. A simple analysis based on the new model is found to be capable of predicting the shapes of microlens which depend on the thermal treatment. For the replication of microlens arrays having various diameters with different foci on the same surface, the hot embossing and the microinjection molding processes has been successfully utilized with a mold insert that is fabricated by Ni-electroplating based on a PMMA microstructure of microlenses. Fabricated microlenses showed good surface roughness with the order of 1 nm.

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