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Speaker: Prof. Jiwang Yan, Professor of Mechanical Engineering at Keio University, Japan

Date: 11 Jan 2019 (Friday)

Time: 11:00 – 12:00

Venue: CF 401

Language: English

(This seminar is open to public.)

 

 

Biography:

Prof. Jiwang Yan obtained his Ph.D. from Tohoku University in 2000 and is currently a professor of Mechanical Engineering at Keio University, Japan, leading the Laboratory for Precision Machining and Nano Processing (PMNP). His research areas include ultraprecision machining, micro/nanomanufacturing, material processing, and nanomechanics. His lab explores multidisciplinary R&D by interfacing manufacturing technology with mechanical science, material science, nanoscience, chemistry, and physics. He has led the implementation of tens of research projects supported by governments and industry to develop key fabrication processes for optics, molds, cutting/grinding tools, semiconductor substrates, battery electrodes, and biomechanical components. He has received more than 30 awards from academic societies and scientific foundations for his contributions in research. He is now a member of the Japan Society of Mechanical Engineers (JSME), Japan Society for Precision Engineering (JSPE), Japan Society for Abrasive Technology (JSAT), Japan Society for Applied Physics (JSAP), American Society for Precision Engineering (ASPE), European Society for Precision Engineering and Nanotechnology (euspen), and the International Academy for Production Engineering (CIRP). He also serves on the editorial boards for several academic journals, such as the International Journal of Machine Tools and Manufacture (IJMTM).

Abstract:

Thin optics are required in various optical systems to reduce the size, weight and production cost of the systems. However, thin optics are difficult to fabricate due to the low stiffness of the substrates. In this talk, recent research outcomes of the speaker's group on ultraprecision fabrication of thin optics will be highlighted. Two examples will be given. First, a hybrid fabrication process for manufacturing thin-film metal Fresnel lenses for X-ray applications by combining photolithography and diamond turning technologies will be introduced. This method was successful to prevent deflection of thin-film lens substrates during diamond turning, so that a 10 micron-thick copper film Fresnel lens was fabricated. Second, a hybrid structure of single-crystal silicon (Si) and high-density polyethylene (HDPE) was developed for infrared lenses by using precision press molding. A 60-100 micron thick HDPE film was used to laminate a silicon wafer and their interface was directly bonded by the silane cross-link. The HDPE film is easy to be hot-embossed to form three-dimensional surface microstructures and the silicon wafer provides a high stiffness for the hybrid substrate. The imaging test result shows that the hybrid substrate is capable to produce high image quality, demonstrating that the developed Si-HDPE hybrid substrate is a promising alternative substrate material for IR lenses.