Vacuum deposition of dielectric coatings on volatile material
View Patent ↗In order to allow application of any coating under a vacuum over a volatile gelatinous layer, such as polymer dispersed liquid crystal (PDLC) on an optical glass substrate with a transparent electrode, such as indium tin oxide (ITO) on its surface, a layer of an intermediate stress absorbing polymeric material is first applied to cover the volatile gelatinous layer to prevent evaporation and escape of volatiles, thereafter the coating is applied under a very high vacuum using for example a technique called Physical Vapor Deposition (PVD) or sputtering.
1. A method for directly coating a volatile gelatinous material for use in a high vacuum environment comprising:
applying a layer of volatile gelatinous material onto a substrate;
applying a stress absorbing polymeric layer of adhesive material to the surface of the volatile gelatinous material and allowing it to cure as a coated substrate; thereafter
imposing a high vacuum upon the coated substrate; and
coating the stress absorbing polymeric layer of the coated substrate with intended materials by physical vapor deposition, wherein said intended materials are dielectric layers formed in pairs of low and high index of refraction materials.
2. The method according to claim 1 wherein the volatile gelatinous material is polymer dispersed liquid crystal.
3. A method for directly applying dielectric layers to polymer dispersed liquid crystal material for use in a high vacuum environment to form an electro-optic modulator comprising:
applying a layer of polymer dispersed liquid crystal onto a substrate having an optically-transparent electrode on its surface;
applying a stress absorbing polymeric layer of adhesive material to the surface of the polymer dispersed liquid crystal; and
coating the stress absorbing polymeric layer with a plurality of layers of dielectric material by physical vapor deposition to form a mirror.
4. The method according to claim 3 wherein said plurality of dielectric layers have a reflectivity at a specific wavelength band at which the electro optic modulator operates.