Metal-based transparent heat mirror for ultraviolet curing applications

Metal-based transparent heat mirror for ultraviolet curing applications was designed in terms of induced transmission principle, good ultraviolet transparency and high infrared ray (IR) reflection properties can be obtained by the means of optimal layers design. After a comprehensive analysis to materials properties, TiO2/Ag/TiO2 nano-multilayers with a Ultraviolet (UV) transmission of 81% (at 365 nm) and an IR reflectivity of 90% (at 1600 nm) were designed and prepared by conventional evaporation. The multilayers exhibit a sharp interface between dielectric and metal layers by spectroscopic ellipsometry analysis. The experiment results prove that critical thickness of metal layer determined in light of admittance match and skin effect has no applicable meaning in long-wavelength UV region. Dependence of transmittance in near UV spectra on the thickness of metal layer is less sensitive than that in near IR. This transparent heat mirror can be applied in the “windows” of ultraviolet curing system for heat insulation.