Sumitomo Chemical Develops Ultra-Low Refractive Index Optical Thin Film Coating

Sumitomo Chemical has developed a coating solution that forms transparent thin films with a refractive index of 1.06 at 550 nm, one of the world's lowest levels for practical applications. The films, formed by spin coating then heating or UV irradiation, can be tuned from 1.06 to 1.36 and offer up to 4 µm thickness, 99.9% transmittance (400-700 nm), heat resistance to 300°C and high solvent resistance. Sample provision is scheduled to begin this year.

Key facts

Market context

Low refractive index materials are used to make optical stacks that reflect less light and guide light more efficiently, so they matter in image sensors, displays, lenses and optical communication parts. Demand for these films is driven mainly by consumer electronics cameras, augmented and virtual reality headsets, and the growing use of light-based data links between chips. Specialty coating resins of this kind are typically sold in small, high-value volumes, and a new option with a wider refractive-index range can let device makers fine-tune optical layers without changing their processes. For chemical suppliers, such launches add competition in optical-grade polymers, where performance such as transparency, heat resistance and solvent resistance often matters as much as price. Buyers in this segment usually judge materials on qualification testing and supply reliability, so sample availability is an early signal of how quickly a product may reach production lines.

Source: official release on sumitomo-chem.co.jp. Summary and context written by Market Krystal.