PROCESS FOR FABRICATING A MASK WITH SUBMILLIMETRE APERTURES FOR THE PRODUCTION OF A SUBMILLIMETRE GRID, AND SUBMILLIMETRE GRID

摘要

#CMT# #/CMT# Production of a mask on part of a functional glass substrate involves (a) applying a first layer using a solution of stabilized, dispersed colloidal particles in a solvent and (b) drying the first layer until a mask-forming network of straight-sided interstices is formed. #CMT# : #/CMT# An independent claim is included for a grid produced by the process, having a ratio of spacing between the strands to width of the strands of 7-20. #CMT#USE : #/CMT# The use of the grids obtained by the process is claimed as active layer in an electrochemical and/or electrocontrol device with variable optical and/or energy properties; a photovoltaic device; a heating device; a flat lamp device; an electromagnetic screening device; or any other device requiring a transparent conductive layer. The process is also useful in the fields of glazing (e.g. in buildings, trains, aircraft, cars or boats), visual or display screens (e.g. projection, television, computer or touch screens), lighting surfaces, heating glazing or mirrors. #CMT#ADVANTAGE : #/CMT# Grids showing good optical and electrical conductivity properties are obtained by an inexpensive procedure. The size of the strands can be varied in a range from tens of microns to hundreds of nanometers by adjusting the deposited amount of colloid. #CMT#CERAMICS AND GLASS : #/CMT# Preferred Process: A material (specifically electrically conductive material) is deposited through the mask to fill part of the depth of the interstices, optionally followed by removal of the first layer to reveal a grid of the material. The network of interstices is optionally cleaned (specifically using a plasma source at at atmospheric pressure) before formation of a deposit. The stages of the process are carried at atmospheric pressure and ambient temperature. The aqueous colloidal solution (preferably containing acrylic copolymers) is deposited by liquid techniques. The drying parameters are optionally varied. A grid with a contrast value of 1-20% is obtained by varying the spacing to width ratio of the strands, specifically by varying controlling parameters selected from the coefficient of friction between the compacted colloids and the substrate surface, the nanoparticle size, the initial particle concentration, the nature of the solvent and the thickness (dependent on the deposition technique). Preferred Product: The grids obtained by the process contain random motifs and are deposited on a functional substrate of glass, plastics or mineral material. The substrate coated with the grid has a light transmission of 70-86%. #CMT#POLYMERS : #/CMT# Preferred Materials: The aqueous colloidal solution contains acrylic copolymers. #CMT#EXAMPLE : #/CMT# Substrates were coated by spin-coating methods using simple aqueous emulsions of Neocryl XK 52 (RTM: stabilized colloidal particles based on acrylic copolymer; size 80-100 nm), followed by drying to give (without stoving) a grid structure with characteristic strand widths (A) and inter-strand spacings (B), variable as a function of the concentration and coating speed. At a colloid concentration of 20 wt. % the (A) and (B) values (in mu m) were 5 and 25 at a coating speed of 5 cm per minute, 1 and 7 at 10 cm per minute, 1 and 8 at 30 cm per minute and 1.5 and 13 at 60 cm per minute. At a colloid concentration of 40 wt. % the (A) and (B) values (in mu m) were 4 and 50 at 5 cm per minute, 3.5 and 40 at 10 cm per minute, 2 and 22 at 30 cm per minute and 2.2 and 25 at 60 cm per minute.