Infrared transparent optical elements

Infrared transparent optical elements

NALUX is expanding the application of plastic optical elements by molding resin having special characteristics such as infrared transmissive and high heat resistance, not found in general resin optical materials. NALUX also develops resin materials in collaboration with material manufactures.

Infrared transparent plastic lens (HDPE lens)

Optical lenses for the infrared range are made of germanium (Ge), chalcogenide glass, or silicon, which are special materials different from those used in the visible light range. However, these are expensive because of the high cost of the materials themselves and the difficulty of processing. In addition, some materials contain toxic substances and require careful handling. To solve these problems, NALUX has been proposing resin optical elements made of high-density polyethylene, a non-toxic resin material, for the far-infrared field.

HDPE is a resin material with light transmittance in the infrared range. However, its internal transmittance is low, and sufficient light transmittance cannot be obtained with ordinary lens shapes. NALUX has realized an infrared lens with sufficient transmittance despite being made of resin by reducing the thickness of the lens to the utmost limit using Fresnel lens shape, made with micro fine processing and injection molding technologies. (JP5584870)
This lens is ideal for relatively low-resolution applications, such as spatial temperature sensors, and for systems with strict cost requirements. It can be used not only as a lens, but also as an optical cover or window.
For applications requiring higher resolution, we propose a reflective optical system using plastic free-form mirrors.


  • Low cost because of injection mold production process suitable for volume production
  • HDPE materials offer good availability and stable supply
  • Compact and light weight
  • Chemically stable and high chemical resistance

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