Development of Novel Transmissive Light-Diffusing Material based on the Control of Disorder

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K22062
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: Osaka University
• Principal Investigator: SAITO Akira 大阪大学, 工学研究科, 准教授 (90294024)
• Project Period (FY): 2019-06-28 – 2022-03-31
• Keywords: ナノ構造 / 乱雑さ / 透過光 / モルフォ蝶 / ディフューザー / 採光窓 / バイオミメティクス / 照明

Outline of Final Research Achievements

This project aims for the development of a new transmissive light-diffusing material based on the unique optical properties of Morpho butterflies, especially "nano-disorder". A new "Morpho-type light diffuser" having "high transmittance, wide-angle spread, and no color dispersion" at the same time was enabled by contriving a "nanoscale random structure" limited at the incident interface of the material. After feedback among the design, trial production and verification, it showed performance close to the design value of "transmittance of 85%, FWHM 66° in angular spread, and no wavelength dispersion", and it was found that it surpasses the conventional-type diffusers in both transmittance and diffusivity. We also confirmed anisotropic diffusion that was enabled by the anisotropic structural design, which was difficult with the conventional type. From the above points, we were able to demonstrate the effectiveness of the Morpho-type optical diffuser.

Free Research Field

応用光学、表面科学、バイオミメティクス、放射光、プローブ顕微鏡

Academic Significance and Societal Importance of the Research Achievements

「高透過率・広角拡散・波長分散なし」を並立する従来にない「モルフォ型透過光拡散材」について、構想だった当初段階から、設計・実作による基本性能の実証ができた。これにより、理想的な採光窓、およびディフューザーへ開発の道筋が開けた。冒頭の3条件を並立できるだけでなく、フィルム状でコンパクトな上、特に拡散後の光形状制御が可能な点は、従来型に全くない特長である。まず省エネルギーで価値が高い上、ディフューザーは照明への応用に大きな意義がある。特に明るさ・光効率に加えて演色性、つまりカラーレンダリングにおいて色再現性の高さ、の点で従来の照明に対する大きな変革になり得る。