Eyeglasses are used by more than 1B of people all over the world to correct vision problems. Eyeglasses are coated by several layers in order to serve for the particular patient's needs and also to withstand the continuous and for long-term use. For that reason, the accurate characterization of the individual layers such as Anti-Reflective (AR) layer thickness, overall broadband reflectance, Hard-Coat (HC) thickness, hydrophobic layer thickness, is of high importance.
The AR coating improves vision, reduces eye strain and make eyeglasses look more attractive. Modern AR coatings almost eliminate the reflectance of light for eyeglass lenses and allow for >99% light to pass through the lens and enter the eye.
On the other hand, the HC serves as anti-scratch layer for daily long-term use of eyeglasses. The HC layer needs to have a minimum thicknesses to serve adequately and thus it is important to measure accurately and in non-destructive way the related thickness.
Last but no least, the hydrophobic layer has water- and oil repellent properties to facilitate the cleaning of the lenses. This layer is ultra thin and its important to measure fast and accurately its thickness to secure its long term properties.
FR-tools equipped with the handy ContactProbe (either the standard one or custom-made ones) allow for accurate, reproducible and user-friendly measurement of eyeglass reflectance over the spectral range of interest and the thicknesses of the individual thicknesses.
Typical Application Notes: