Infrared lens units using chalcogenide glass with high transmission properties

Abstract

Germanium and chalcogenide glasses are used as infrared lens materials, but there is no one that combines both excellent optical properties and mass production. Against this background, we worked on the development of a new infrared lens material, and a novel infrared lens material named FI-02 has been developed. FI-02's most useful feature is its infrared transmission property. It can transmit up to 20-μm-wavelength infrared light and has a vast transmittance spectrum in the infrared region compared to germanium and conventional chalcogenide glass. In addition, FI-02 has a high refractive index of 3.47 (at a wavelength of 10 μm). This enables the fabrication of thin and high-performance infrared lenses. Furthermore, FI-02 can be processed through press molding. This enables making of highperformance lenses with high productivity. In an infrared lens unit using FI-02, infrared images are captured with better contrast as compared to those captured using the germanium or conventional chalcogenide glass lenses. This could be attributed to the good infrared transmission property of FI-02. In addition, we confirmed that using FI-02 with a high refractive index as an aspheric lens, it is possible to design a lens unit with unprecedented characteristics, such as a low-distortion ultra-wideangle lens.