– Reflectance reduced to 1/10 or less than that of conventional wire grid polarizers –
Researchers: HOKARI Ryohei, Researcher, Optical Micro and Nano Systems Research Team, Research Center for Ubiquitous MEMS and Micro Engineering, and KURIHARA Kazuma, Senior Researcher, Surface Interaction Design Group, Advanced Manufacturing Research Institute
The researchers have developed a low reflectance wire grid polarizing sheet by creating a wire grid structure using metallic ink, in collaboration with Ryoko Chemical Co., Ltd., Tokai Seimitsu Industrial Co., Ltd., and Itoh Optical Industrial Co., Ltd. The developed polarizing sheet shows a degree of polarization of 99% or more and reflectance of 5% or less, which is 1/10 or less than the conventional reflectance of 51%.
The developed low reflectance, highly durable polarizing sheet
Polarizers are optical elements that support polarization control technology, which is essential not just for liquid crystal displays but also a wide range of fields, for example optical equipment such as liquid crystal projectors, automotive equipment such as head-up displays, manufacturing equipment such as liquid crystal exposure devices, and polarized sunglasses. However, high durability (heat resistance, moisture resistance, light resistance) is demanded of the elements that comprise products, such as automotive equipment and liquid crystal projectors.
Conventional wire grid polarizers combine the features of a high degree of polarization, high transmittance, and thinness. However, the reflectance is high, so application has been limited to products such as liquid crystal projectors.
The researchers combined nanoimprint technology and printing technology and used metallic ink with proper firing to form a wire grid structure that achieves a high aspect ratio and a width narrower than the wavelength of visible light. This realized the world’s first low reflectance wire grid polarizing sheet with a degree of polarization of 99% or more and reflectance of 5% or less.
This technology enabled to reduce the reflectance while making the most of the features of conventional wire grid polarizers. Heat resistance, moisture resistance, light resistance, and scratch resistance are also provided, so in addition to the optical field, applications can also be expected in sectors for which application had been a challenge thus far, such as the eyewear industry and the automotive industry.
This research applied printing technology to reduce the reflectance of the wire grid polarizing element, and the researchers intend to promote further research and development to achieve a good balance between the degree of polarization and transmittance.