Plastic articles having multi-layer antireflection coatings, and sol-gel process for depositing such coatings

A process for depositing a multi-layer antireflection coating on a plastic substrate, comprising the steps of:

• mixing one or more first polymerized, non-organic solutions consisting essentially of an alkoxide, an alcohol, and water, wherein the one or more first polymerized solutions are formulated to provide thin films having a refractive index of 1.80 or more;
• mixing one or more second polymerized, non-organic solutions consisting essentially of an alkoxide, an alcohol, and water, wherein the one or more second polymerized solutions are formulated to provide thin films having a refractive index of 1.46 or less;
• applying a first polymerized solution and a second polymerized solution to the plastic substrate, in an alternating fashion, wherein a prescribed amount of the solution adheres to the substrate following each step of applying;
• and
• following each step of applying, curing the adhered solution, before the next successive step of applying occurs, each such step of curing forming a separate, polymerized layer on the substrate, wherein the successive polymerized layers cooperate to form a multi-layer coating of at least four layers that provides substantially reduced reflectivity of visible light.

A process for depositing a multi-layer antireflection coating on a plastic substrate, comprising the steps of:

• providing a first polymerized, non-organic, titanium-containing solution consisting essentially of the following ingredients, in the indicated proportions
• 1.0 moles of a titanium alkoxide selected from the group consisting of titanium isopropoxide, titanium propoxide, and titanium ethoxide
• 80 to 120 moles of ethyl alcohol,
• 2 to 5 moles of deionized water, and
• 0.05 to 0.05 moles of an acidic catalyst selected from the group consisting of hydrochloric acid and nitric acid;
• providing a second polymerized, non-organic, titanium-containing solution consisting essentially of the following ingredients, in the indicated proportions
• 1.0 moles of a titanium alkoxide selected from the group consisting of titanium isopropoxide, titanium propoxide, and titanium ethoxide
• 35 to 55 moles of ethyl alcohol,
• 2 to 5 moles of deionized water, and
• 0.1 to 0.4 moles of an acidic catalyst selected from the group consisting of hydrochloric acid and nitric acid;
• providing a first polymerized, non-organic, silicon-containing solution consisting essentially of the following ingredients, in the indicated proportions
• 1.0 moles of a silicon alkoxide selected from the group consisting of tetraethyl orthosilicate and tetramethyl orthosilicate,
• 70 to 90 moles of ethyl alcohol,
• 2 to 6 moles of deionized water, and
• 0.1 to 0.3 moles of an acidic catalyst selected from the group consisting of hydrochloric acid and nitric acid;
• providing a second polymerized, non-organic, silicon-containing solution consisting essentially of the following ingredients, in the indicated proportions
• 1.0 moles of a silicon alkoxide selected from the group consisting of tetraethyl orthosilicate and tetramethyl orthosilicate,
• 25 to 35 moles of ethyl alcohol,
• 2 to 5 moles of deionized water, and
• 0.05 to 0.1 moles of an acidic catalyst selected from the group consisting of hydrochloric acid and nitric acid;
• applying the first polymerized, titanium-containing solution to a substrate formed of a material methacrylate, polystyrene, polycarbonate, allyl diglycol carbonate, and polyethylene terephthalate, wherein a prescribed amount of the solution adheres to the substrate;
• curing the adhered solution to form a first polymerized layer, the layer including polymerized titanium dioxide and having a prescribed uniform thickness and an index of refraction in the range of 1.80 to 2.20;
• applying the first polymerized, silicon-containing solution to the coated substrate, wherein a prescribed amount of the solution adheres to the coated substrate;
• curing the adhered solution to form a second polymerized layer, the layer including polymerized silicon dioxide and having a prescribed uniform thickness and an index of refraction in the range of 1.40 to 1.46;
• applying the second polymerized, titanium-containing solution to the coated substrate, wherein a prescribed amount of the solution adheres to the coated substrate;
• wherein the first, second, third and fourth layers cooperate to form an antireflection coating that provides substantially reduced reflectivity of visible light.

A process for depositing a polymerized titanium dioxide, thin-film optical coating on a plastic substrate, comprising:

• providing a polymerized, non-organic, titanium-containing solution consisting essentially of a titanium alkoxide, an alcohol, and water;
• applying the titanium-containing solution to the plastic substrate such that a prescribed amount of the solution adheres to the substrate, wherein applying occurs within a coating chamber in which the relative humidity is at least 40%;
• and
• curing the adhered titanium-containing solution to form a polymerized titanium dioxide, thin-film optical coating on the substrate.

A process for depositing a polymerized silicon dioxide, thin-film optical coating on a plastic substrate, comprising:

• providing a polymerized, non-organic, silicon-containing solution consisting essentially of a silicon alkoxide, an alcohol, and water;
• applying the silicon-containing solution to the plastic substrate such that a prescribed amount of the solution adheres to the substrate, wherein applying occurs within a coating chamber in which the relative humidity is less than 40%;
• and
• curing the adhered silicon-containing solution to from a polymerized silicon dioxide, thin-film optical coating on the substrate.