Fluorinated and hydrogenated diamond-like carbon materials for anti-reflective coatings

Abstract

Fluorinated and hydrogenated diamond-like carbon ('DLC-FH') that have unique optical properties differ as a class from the existing DLC art, whose refractive indices [η]are limited to rather high values above a lower threshold of 1.7, and can range up to about 2.7. The DLC-FH materials can achieve very low refractive indices at 550 nm wavelength, [η], i.e., below 1.5, and especially demonstrated down to 1.3. Moreover, whereas the absorption for the existing DLC art, as quantified by the extinction coefficient [κ] at a wavelength of 550 nm, [κ] is limited to about 0.04, our DLC-FH material can achieve [κ] below 0.01. Both of these attributes, i.e., low [η] and low [κ] means that, for the first time, a carbon-based material as represented by the DLC-FH material, can be used for anti-reflection (AR) coating, wherein there are no longer any restrictions in how they can be used to promote low reflectance (with low fit[η]) and high transmittance (with low [κ]). A dual-energy deposition process, using a Laser Arc for the high energy component creates a plasma of energized carbon atoms and ions, and excites a down-stream flow of fluorine and hydrogen containing gases to deposit an AR coating on a substrate which may be, windows typical of transportation vehicles (land, sea, air), and buildings.