Method of applying a uniform polymer coating
View Patent ↗A method of applying a polymer coating uses a nebulized aerosol of solubilized polymer solution having high-viscosity droplets and low-viscosity droplets to form a textured antireflective surface. Air or other gas is used to direct the nebulized aerosol toward the surface of an object. In some embodiments, heated or dried air, such as from an air curtain, is used to promote the formation of high-viscosity droplets. In a particular embodiment, multiple ultrasonic nebulizers are used in combination with synchronized air jets to apply a uniform polymer coating onto a glass panel used in a large-format display system. Dye is optionally added to the solubilized polymer solution to provide a notch filter at 585 nm and/or infrared filter.
1. A method of applying a transmissive polymer coating having a textured antireflective surface comprising:
forming a nebulized aerosol from a solubilized polymer solution;
directing the nebulized aerosol toward a surface of an object to wet the surface; and
drying the solubilized polymer solution to form the transmissive polymer coating having the textured antireflective surface, wherein the nebulized aerosol includes low-viscosity droplets of the solubilized polymer solution and high-viscosity droplets of the solubilized polymer solution, and, after the drying step, at least a portion of the high-viscosity droplets extending above an essentially continuous polymer film of the transmissive polymer coating to form the textured antireflective surface.
2. The method of claim 1 wherein the step of directing includes providing an air jet to direct the nebulized aerosol toward the surface.
3. The method of claim 2 wherein the directing step further includes heating the air jet.
4. The method of claim 1 further comprising steps of
moving the surface along a first direction; and
oscillating the air jet to distribute the nebulized aerosol transverse to the first direction.
5. The method of claim 4 wherein the step of directing includes providing a second air jet, and the step of oscillating includes synchronizing the second air jet with the air jet.
6. The method of claim 1 further comprising a step, prior to forming the nebulized aerosol, of mixing a dye with the solubilized polymer solution in a concentration chosen to avoid phase separation of the dye from both the high-viscosity droplets and the essentially continuous polymer film.
7. The method of claim 6 wherein a thickness of the essentially continuous polymer film and the concentration of the dye are chosen to provide a selected absorption of light.
8. A method of applying a transmissive polymer coating having a textured antireflective surface comprising:
forming a nebulized aerosol from a solubilized polymer solution; directing the nebulized aerosol toward a surface of an object to wet the surface; and
drying the solubilized polymer solution to form the transmissive polymer coating having the textured antireflective surface, wherein the nebulized aerosol comprises, before the step of directing, a heterogeneous dispersion of polymer solution particles having a first mean size distribution, and before wetting the surface, the nebulized aerosol comprises a heterogeneous dispersion of polymer solution particles having a second mean size distribution.
9. A method of applying a transmissive polymer coating having a textured antireflective surface comprising:
forming a first nebulized aerosol from a first solubilized polymer solution;
directing the first nebulized aerosol toward a surface of an object to form a continuous polymer film;
forming a second nebulized aerosol from a second solubilized polymer solution;
directing the second nebulized aerosol toward the continuous polymer film particles in the second nebulized aerosol having viscosity selected to adhere to the continuous polymer film and at least partially extend above the continuous polymer film to form a textured polymer film; and
drying the textured polymer film to form the transmissive polymer coating having the textured antireflective surface, wherein a surface of the continuous polymer film has viscosity between about 25,000 cps and about 150,000 cps and particles in the second nebulized aerosol having viscosity greater than about 5,000 cps.