Method for applying an antireflection coating to inorganic optically transparent substrates
First Claim
1. A method for applying an antireflection coating to a substrate of an optically transparent, inorganic material, wherein alternating layers of different refractive indices are applied to the substrate by means of a plasma-enhanced PVD process, more particularly by so-called sputtering, the distance between the target and the substrate being chosen such that the scratching resistance of the obtained layers is similar to or higher than that of the substrate.
2 Assignments
0 Petitions
Accused Products
Abstract
An antireflection coating having a high abrasion and scratching resistance can be applied to natural glass by sputtering, the substrates being positioned closer to the target than usual in order to obtain an increased density of the applied layers. An irregular deposition rate can be compensated by moving the substrate, thus allowing to ensure a regular thickness and therefore a high optical quality of the antireflection coating in these conditions as well. On the preferred sapphire watch glass, SiO2 and Si3N4 resp. AlN and Al2O3 can be used for the individual layers, in particular. These layers do not have a noticeable color effect, but on account of their high hardness, their abrasion and scratching resistance is comparable to that of sapphire glass.
41 Citations
14 Claims
- 1. A method for applying an antireflection coating to a substrate of an optically transparent, inorganic material, wherein alternating layers of different refractive indices are applied to the substrate by means of a plasma-enhanced PVD process, more particularly by so-called sputtering, the distance between the target and the substrate being chosen such that the scratching resistance of the obtained layers is similar to or higher than that of the substrate.
Specification