Photonic Cooler IR Filter Coating With Stable Oxide-Metal Stack

The patent uses composite material structures (MoOx/Ag/MoOx and TCO/metal/TCO stacked layers) where metal oxide layers protect the metal layer from oxidization while maintaining infrared reflection capability. The composite structure combines the high infrared reflectivity of metals with the environmental stability of metal oxides.

Metal oxide layers (MoOx or TCO) are introduced as intermediary protective layers between the metal layer and the environment. These intermediary layers prevent direct contact between moisture/oxygen and the metal, eliminating oxidization and delamination issues while allowing infrared radiation to pass through.

The patent changes the stoichiometry parameter of MoOx layers, using non-stoichiometric MoOx with oxygen deficiency to create a gradient structure. This parameter change reduces oxygen diffusion barriers and prevents the formation of fractured films while maintaining protective functionality.

The patent applies different oxygen concentrations at different positions within the MoOx layers, creating a gradient structure where oxygen content varies through the thickness. This local quality variation allows the layer to simultaneously protect against oxidization at the metal interface while maintaining film integrity at the outer surface.

The patent replaces expensive and complex doped TCO materials with simpler, cheaper metal oxide layers (MoOx) that can be deposited using conventional techniques. This substitution maintains the protective functionality while dramatically reducing material cost and simplifying the manufacturing process for large-scale production.

The patent optimizes the thickness parameters of MoOx layers (using thinner layers compared to doped TCO) to achieve the desired infrared cutoff performance. By changing the thickness parameter, the filter achieves high infrared reflection with lower material usage, improving both performance and manufacturability.