Ultraprecision forming of hybrid Fresnel lenses using infrared-transparent polymer and single-crystal silicon

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03159
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Production engineering/Processing studies
• Research Institution: Keio University
• Principal Investigator: YAN JIWANG 慶應義塾大学, 理工学部(矢上), 教授 (40323042)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: プレス成形 / フレネルレンズ / 赤外線素子 / 光学部品 / 複合レンズ / 超精密切削 / マイクロ加工

Outline of Final Research Achievements

A hybrid structure of single-crystal silicon (Si) and high-density polyethylene (HDPE) was developed for infrared lenses by using precision press molding. A thin HDPE film was used to laminate a silicon wafer and their interface was directly bonded by the silane cross-link. The HDPE film was hot-embossed to form three-dimensional surface microstructures and the silicon wafer provides a high stiffness for the hybrid substrate. The infrared (IR) optical properties of the hybrid substrate were examined and the imaging test result shows that the hybrid substrate was capable to produce practical image quality. These results strongly demonstrate that the developed Si-HDPE hybrid substrate is a promising alternative substrate material for IR lenses. The interface phenomenon between Si and HDPE was investigated and the lens forming mechanisms were analyzed, as well as the optimal forming conditions were explored.

Free Research Field

超精密加工

Academic Significance and Societal Importance of the Research Achievements

本研究で提案したHDPE薄肉層による単結晶Siウエハの内包多層構造を用いた厚さ1mm未満の超薄型フレネルレンズの製作は前例のない試みである．特に数十ミクロンスケールの微細形状転写とSi/HDPEの界面接合を一括して実現できた点は大きな成果であると言える．また，単結晶SiとHDPEとの架橋結合における界面現象の解明は加工学へ重要な知見を与えたものであると考えられる．さらに，本研究成果は暗視カメラ，車載ナイトビジョン装置，夜間防犯カメラ，温度センサー，セキュリティー・体温検査，火災検知など幅広い製品への応用が可能であり，ものづくり産業への波及効果も大きい．