| abstract |
The invention relates to a glass substrate having on at least one of its faces an antireflection coating formed by a stack of thin dielectric material layers having alternately high and low refractive indices. To prevent the modification of the optical properties of the coating in the case where the substrate is subject toga heat treatment such as tempering, bending or annealing, the layer or layers of the stack which are liable to deteriorate on contact with alkali ions such as sodium ions are separated form the substrate by at least one layer forming part of the antireflection coating and forming a "shield" with respect to the diffusion of alkali. |