| 摘要 |
The invention relates to antireflective coatings and to a process for depositing the antireflective coatings on solar collector cover plates, optical elements such as lenses and windows in high-energy visible and near-IR lenses and on other glass or metal or metal-alloy or single crystal surfaces, including the steps of hydrolyzing an alkoxysilane, titanium alkoxide, aluminum alkoxide, tantalum alkoxide, niobium alkoxide, or other alkoxy compounds, or a mixture thereof, depending upon the final coating composition desired; to prepare polymeric solutions of the alkoxy compound/or compounds in which the polymer molecules or macromolecules (i.e. the primary particles) grow with time; depositing layers of coatings from the polymeric solutions by state of the art processes (such as spraying, dipping or spinning method), and drying to form chemically bound microporous gel layers; thermally treating the gel-coating in a manner adapted to remove solvent, excess water and residual organics from the gel coating. Microporous coatings produced by the above procedure will be characterized by graded particles and hence graded porosity across the coating thickness, -larger porosity on the top surface and smaller porosity in the substructure-, and will have gradual transition of refractive index (i.e. graded refractive index) across the coating thickness. Coatings produced by the process of this invention can be used to reduce or eliminate reflection losses from surfaces of transmitting optical elements over a wide spectrum of light waves.
|
