Koike, Yasuhiro

写真a

Affiliation

Keio Frontier Research & Education Collaborative Square (K-FRECS), K-FRECS at Shin-Kawasaki (Mita)

Position

Project Professor (Non-tenured)
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Other Affiliation 【 Display / hide 】

  • Keio Photonics Research Institute, Director

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Career 【 Display / hide 】

  • 1982.04
    -
    1983.03

    Keio University, Faculty of Science and Technology, 非常勤講師

  • 1983.04
    -
    1988.03

    Keio University, Faculty of Science and Technology,  助手

  • 1988.04
    -
    1992.03

    Keio University, Faculty of Science and Technology, 専任講師

  • 1989.04
    -
    1990.02

    AT&T Bell Laboratories, Visiting Researcher

  • 1992.04
    -
    1997.03

    Keio University, Faculty of Science and Technology,  助教授

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Academic Background 【 Display / hide 】

  • 1977.03

    Keio University, Faculty of Engineering, Department of Applied Chemistry

    University, Graduated

  • 1979.03

    Keio University, Graduate School, Division of Engineering

    Graduate School, Completed, Master's course

  • 1982.03

    Keio University, Graduate School, Division of Engineering

    Graduate School, Completed, Doctoral course

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Academic Degrees 【 Display / hide 】

  • Master of Science in Engineering , Keio University, Coursework, 1979.03

  • PhD in Engineering, Keio University, 1982.03

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Research Areas 【 Display / hide 】

  • Nanotechnology/Materials / Polymer chemistry (Photonics Polymer)

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Research Keywords 【 Display / hide 】

  • Graded Index Plastic Optical Fiber, Zero-Birefringence Polymers

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Books 【 Display / hide 】

  • Fundamentals of Plastic Optical Fibers

    Wiley-VCH, 2015.01

  • 透明ポリマーの材料開発と高性能化

    シーエムシー出版, 2015

    Scope: 第16章　プラスチック光ファイバー

  • Encyclopedia of Polymeric Nanomaterials

    Yasuhiro Koike and Kenji Makino, Springer, 2015

    Contact page： 1902-1913

  • Handbook of Fluoropolymer Science and Technology

    Y. Okamoto, F. Mikes, K. Koike, and Y. Koike, Wiley, 2014.05

    Scope: Amorphous Perfluoropolymers

  • 高分子ナノテクノロジーハンドブック～最新ポリマーABC技術を中心として～

    （株）エヌ・ティー・エス, 2014.03

    Scope: 第2章　IT・エレクトロニクスイノベーション：電気電子デバイスの高度化　第5節　フォトニクスポリマーデバイス

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Papers 【 Display / hide 】

  • Graded-index plastic optical fiber for needle-sized lens and rigid endoscope

    Yamashita H., Koike I., Nakamura M., Koike Y.

    Proceedings of SPIE - The International Society for Optical Engineering 13389 2025

    ISSN  0277786X

    　View Summary

    We have been developing a graded-index plastic optical fiber (GI-POF) for a needle-sized lens and a rigid endoscope. With highly accurate control of refractive index within a plastic lens, we can utilize it for an ultra-fine lens as a replacement for a relay lens or fiber-bundled lens in conventional rigid endoscopes. The 0.5-mm diameter lens performs high resolution with about 200-line pairs/mm. For endoscope imaging, we used optical and digital correction of chromatic aberration caused by material properties of GI-POF lens. The rigid endoscope with the GI-POF lens has a possibility to allow doctors to directly observe a patient's inner affected area before and after surgery in a minimally invasive procedure, enabling rapid and accurate assessment of the patient's condition and efficient post-operative followup.

  • Randomizing polarization of displays for fundamental improvement of color mura caused by birefringence

    Sasaki S., Koike Y.

    Optics Letters 49 ( 22 ) 6501 - 6504 2024.11

    ISSN  01469592

    　View Summary

    Most existing displays utilize polarization technologies to produce images and improve image quality. However, polarized light from displays causes color mura because of the birefringence of the polymer films used. Thus, eliminating color degradation remains a challenge despite the incorporation of complex polarization technologies such as retardation films. Our proposed random depolarization film (RDF) addresses this issue by randomizing the polarization of light from displays. Chromaticity measurements demonstrate that the RDF effectively compensates for color mura due to low-cost polymer films. Notably, the RDF compensation mechanism is independent of the RDF position and light source spectrum. Therefore, the RDF could be an innovative solution for color degradation in existing displays.

  • Random depolarization film design based on modulation transfer function measurements of displays with different pixel pitches

    Sasaki S., Masaoka K., Koike Y.

    Applied Optics 63 ( 11 ) 2900 - 2905 2024.04

    ISSN  1559128X

    　View Summary

    Polarized light emitted frommost displays causes blackout and color change problems when viewed through polarized sunglasses. These problems are addressed by random depolarization films (RDFs) doped with birefringent particles. These dopant particles, however, scatter light and degrade the sharpness of the displayed images.To maintain the image sharpness, we designed an RDF based on modulation transfer function measurements of displays with different pixel pitches. RDFs doped with larger particles achieved higher modulations; however, particles larger than a specific size caused undesirable sparkles on the displayed image. A display with a larger pixel pitch achieved higher modulations, suggesting that the RDF is particularly suitable for large-screen displays.

  • Stabilized Plastic Optical Fiber Link Even Without a Physical-Contact Fiber Connection

    Muramoto K., Minami H., Koike Y.

    Journal of Lightwave Technology 42 ( 2 ) 875 - 881 2024.01

    ISSN  07338724

    　View Summary

    We propose a novel graded-index plastic optical fiber (GI POF) link that enables stable high-speed data transmission without the requirement for conventional coupling techniques to reduce reflection at fiber connection, as typified by physical-contact (PC) fiber connection, for short-reach multimode fiber (MMF) applications with vertical-cavity surface-emitting lasers (VCSELs). In the novel GI POF link, noise caused by light reflected at the fiber connection back into a VCSEL cavity can be suppressed through strong mode coupling in the fiber. It thereby improves the bit error rate of the data transmission compared with conventional silica and polymer MMFs. The capability of the novel GI POF link will be advantageous for optical interconnects in household and automotive applications, in which PC connection is not ideal to apply. The novel GI POF link will also be invaluable for multi-fiber interconnects based on multi-fiber connectors for data center applications, in which complete PC connections are difficult to obtain.

  • Proposal of Novel Random Depolarization Film for Real-Color Displays with Sharp Images

    Sasaki S., Koike Y.

    Digest of Technical Papers - SID International Symposium 55 ( 1 ) 425 - 428 2024

    ISSN  0097966X

    　View Summary

    The random depolarization film (RDF), a polymer film doped with birefringent particles, converts linearly polarized light to randomly polarized light. This paper shows that a novel RDF with controlled birefringence resolves polarization problems of the display such as blackout, color change, and color mura problems. Furthermore, the novel RDF achieved a higher contrast ratio and a sharper image than a conventional RDF doped with calcite particles.

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Reviews, Commentaries, etc. 【 Display / hide 】

  • 屈折率分布型ポリマー光導波路の歴史と展開

    小池康博

    光技術コンタクト (日本オプトメカトロニクス協会)   2017.05

    Article, review, commentary, editorial, etc. (scientific journal), Single Work

  • 新川崎タウンキャンパスの発展とこれからー研究活動を中心に

    小池康博

    三田評論 (慶應義塾)   2016.12

    Article, review, commentary, editorial, etc. (bulletin of university, research institution), Single Work

  • ボールペン技術から生まれたGI-POF用光コネクタ

    三井章仁、小池 康博

    光アライアンス2016年3月号 (日本工業出版)   2016.03

    Article, review, commentary, editorial, etc. (scientific journal), Joint Work

  • ディスプレイの高画質化のための光散乱ポリマー材料

    KOIKE YASUHIRO

    光学 (日本光学会)  44 ( 8 ) 310 - 315 2015.08

    Article, review, commentary, editorial, etc. (scientific journal), Joint Work

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Presentations 【 Display / hide 】

  • Graded-index plastic optical fiber for needle-sized lens and rigid endoscope

    H. Yamashita, I. Koike, M. Nakamura and Y. Koike

    SPIE Photonics West 2025 (San Francisco, California USA) , 

    2025.01
    , 

    Oral presentation (invited, special)

  • Error-Free POF for Beyond 5G and AI Technology

    YASUHIRO KOIKE

    The 32nd International Conference on Plastic Optical Fibers (POF2024) (Tokyo, Japan) , 

    2024.11
    , 

    Oral presentation (invited, special)

  • Proposal of Error-Free GI POF for Beyond 5G Society

    YASUHIRO KOIKE, KENTA MURAMOTO

    16th Pacific Rim Conference on Lasers and Electro-Optics (CLEO-PR 2024) (Incheon, Korea) , 

    2024.08
    , 

    Oral presentation (invited, special)

  • Recent progress in GI POF technologies toward Beyond 5G era

    KENTA MURAMOTO, YASUHIRO KOIKE

    SPIE Photonics West 2024 (San Francisco, California USA) , 

    2024.01
    -
    2024.02
    , 

    Oral presentation (invited, special)

  • Super Big-Data Opticalization and Fibering with GI POF

    D. Weng, Y. Koike, W. White, D. Zhang, B. Ameduri, and Y. Okamoto

    The 31th International Conference on Plastic Optical Fibers (POF2023) (Cork, Ireland) , 

    2023.09
    , 

    Oral presentation (invited, special)

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Research Projects of Competitive Funds, etc. 【 Display / hide 】

  • 屋外でも色変化がなく鮮明な表示ができるディスプレイ用のランダム偏光粘着剤の開発

    2024.04
    -
    2026.03

    経済産業省　関東経済産業局, 成長型中小企業等研究開発支援事業（Go-Tech事業） , No Setting

  • エラーフリーPOFによる革新 的通信システムの開発

    2024.04
    -
    2026.03

    国立研究開発法人 情報通信研究機構（NICT）, 革新的情報通信技術(Beyond 5G(6G))基金事業, Principal investigator

  • エラ ーフリーPOFによる革新的通信システムの開発

    2022.09
    -
    2024.03

    国立研究開発法人 情報通信研究機構（NICT）, Beyond 5G研究開発促進事業, Principal investigator

  • ノイズレスGI型プラスチック光ファイバによる超高速IoT社会の実現

    2017.06
    -
    2018.02

    国立研究開発法人新エネルギー産業技術総合開発機構（NEDO）, IoT推進のための 横断技術開発プロジェクトの周辺技術・関連課題における小規模研究開発, Principal investigator

  • 未来医療を実現する先端医療機器・シス テムの研究開発/安全性と医療効率の向上を両立スマート治療室の開発

    2017.01
    -
    2018.03

    国立研究開発法人日本医療研究開発機構, Coinvestigator(s)

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Works 【 Display / hide 】

  • APS TV 2023 Highligh Research

    2023.03
    -
    Present

  • 日本経済新聞 15面 低ノイズの光ファイバー　プラ製　慶大と日東電工が開発

    日本経済新聞15面, 

    2020.01
    , 

    Other

  • 電波タイムズ　2面「一般社団法人サービス高度化推進協会が実証実験を公開　新4K8K衛星放送の光配信方式の実用化」

    2019.03
    , 

    Other

  • 電波新聞　3面「A-PAB POFシステムによる実証実験　簡単に現場施工、低コスト　外観損なわず既存設備に追加」

    2019.02
    , 

    Other

  • 高分子学会関東支部主催、若手社員のための高分子基礎講座

    小池康博

    平塚, 

    2017.10
    , 

    Other, Single

    　View Details

    光学材料とファンダメンタルズ

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Awards 【 Display / hide 】

  • Fellow, The Society of Polymer Science, Japan

    Yasuhiro Koike, 2021.08,  The Society of Polymer Science, Japan (SPSJ)

    Type of Award： Honored in official journal of a scientific society, scientific journal

  • 2019年度高分子科学功績賞

    小池康博, 2020.05,  The Society of Polymer Science, Japan (SPSJ), フォトニクスポリマーの基礎と機能創出

  • SID Special Recognition Award

    Yasuhiro Koike, 2015.06, The Society for Information Display (SID)

    Type of Award： Award from international society, conference, symposium, etc.,  Country： United States

  • 第24回「向井賞」

    KOIKE YASUHIRO, 2013.05, 公益財団法人東京応化科学技術振興財団, Fundamental Studies and Creation of Functions of Photonics Polymer

  • 第13回「神奈川イメージアップ大賞」

    KOIKE YASUHIRO, 2011.01, 毎日新聞社

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Courses Taught 【 Display / hide 】

  • GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 2

    2023

  • GRADUATE RESEARCH ON INTEGRATED DESIGN ENGINEERING 2

    2022

  • APPLIED PHYSICS AND PHYSICO-INFORMATICS LABORATORY C

    2019

  • APPLIED PHYSICS AND PHYSICO-INFORMATICS LABORATORY D

    2019

  • BACHELOR'S THESIS

    2019

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Social Activities 【 Display / hide 】

  • 日本板硝子材料工学助成会

    2021.06
    -
    2025.06

  • カイロス株式会社　テクニカル・アドバイザー

    2016.12
    -
    2017.12

  • 国立大学法人　神戸大学　非常勤講師

    2016.08

  • 独立行政法人科学技術振興機構　研究成果展開事業「戦略的イノベーション創出推進プログラム（S-イノベ）」研究開発テーマ「フォトニクスポリマーによる先進情報通信技術の開発」プログラムオフィサー補佐

    2014.04
    -
    2015.03

  • 一般財団法人フロンティアサロン　理事　

    2013.09
    -
    Present

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Media Coverage 【 Display / hide 】

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Memberships in Academic Societies 【 Display / hide 】

  • The International Society for Optics and Photonics, 

    2016.01
    -
    Present

  • SPIE, 

    2016
    -
    Present

  • The Society for Information Display, 

    2011.04
    -
    Present

  • 一般社団法人　電子情報通信学会, 

    2011.01
    -
    2015.03

  • Japan Responsinble Care Council, 

    2008.10
    -
    2010.05

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Committee Experiences 【 Display / hide 】

  • 2022.08
    -
    2023.03

    国際科学技術共同研究推進事業（戦略的国際共同研究プログラム）アドバイザー, 国立研究開発法人科学技術振興機構

  • 2019.12
    -
    2020.03

    国際科学技術共同研究推進事業（戦略的国際共同研究プログラム）アドバイザー, 国立研究開発法人科学技術振興機構

  • 2018.09
    -
    2018.11

    Organizing Committee Member, the 24th Microoptics Conference (MOC2019)

  • 2018.03
    -
    2022.04

    日本国際賞審査部会委員, 公益財団法人　国際科学技術財団　

  • 2018.02
    -
    2018.03

    国際科学技術共同研究推進事業（戦略的国際共同研究プログラム）アドバイザー, 国立研究開発法人　科学技術振興機構

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