BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to solar control coatings and, in one particular embodiment, to a solar control coating having increased absorbance or tint.

Technical Considerations

Solar control coatings are known in the fields of architectural and vehicle transparencies. These solar control coatings block or filter selected ranges of electromagnetic radiation, such as in the range of solar infrared or solar ultraviolet radiation, to reduce the amount of solar energy entering the vehicle or building. This reduction of solar energy transmittance helps reduce the load on the cooling units of the vehicle or building.

These solar control coatings typically include one or more continuous metal layers to provide solar energy reflection, particularly in the solar infrared region. Metal layers deposited below a critical thickness (referred to herein as “subcritical layers”) form discontinuous regions or islands rather than a continuous layer. These discontinuous layers absorb electromagnetic radiation through an effect known as surface Plasmon resonance. These subcritical layers typically have higher absorbance in the visible region than a continuous layer of the same material and also have lower solar energy reflectance.

For some applications, tinted glass is desired. Tinted glass is conventionally produced by adding special colorants to the glass batch material. In a float glass process, this addition is time consuming, increases costs, and is potentially harmful to the float tank. Also, it is tedious to transition the float tank from producing tinted glass to glass having a different tint or no tint. Also, tinted glass is typically produced on a campaign basis and then stored for long periods of time, sometimes resulting in spoiling of the tint due to glass corrosion before it can be coated or sold.

It would be desirable to produce a solar control coating in which the absorption of the coating and/or the tint of the glass product could be more easily controlled.

SUMMARY OF THE INVENTION

In one broad aspect of the invention, the coating of the invention includes one or more continuous, infrared reflective metal layers in combination with a subcritical (i.e., discontinuous) metal layer. The discontinuous metal layer increases the visible light absorption of the coating and, in combination with dielectric layers of appropriate thickness, can also provide the coated article with asymmetrical reflectance. The subcritical metal layer includes copper, and optionally a second metal, such as silver.

A coating of the invention comprises a plurality of metallic layers alternating with a plurality of dielectric layers, with at least one of the metallic layers comprising a subcritical metallic layer having discontinuous metal regions. The subcritical metal layer includes copper, and optionally a second metal, such as silver.

A coated article comprises a substrate and a coating stack over at least a portion of the substrate. The coating stack comprises a plurality of metallic layers and a plurality of dielectric layers, wherein at least one of the metallic layers comprises a subcritical metallic layer having discontinuous metallic regions. The subcritical metal layer includes copper, and optionally a second metal, such as silver.

Another coated article comprises a glass substrate and a coating formed over at least a portion of the glass substrate. The coating comprises a first dielectric layer formed over at least a portion of the glass substrate; a continuous metallic layer formed over at least a portion of the first dielectric layer; a second dielectric layer formed over at least a portion of the first metallic layer; a subcritical metallic layer formed over at least a portion of the second dielectric layer such that the subcritical metallic layer forms discontinuous metallic regions wherein the subcritical metal layer includes copper, and optionally a second metal, such as silver; a third dielectric layer formed over at least a portion of the subcritical metallic layer; a third continuous metal layer formed over at least portion of the third dielectric layer; a third dielectric layer formed over at least a portion of the third metal layer; and a protective layer formed over at least a portion of the third metallic layer.

A further coated article comprises a substrate and a coating comprising a first dielectric layer formed over at least a portion of the substrate; a first metallic layer formed over at least a portion of the first dielectric layer; a second dielectric layer formed over at least a portion of the first metallic layer; a second metallic layer formed over at least a portion of the second dielectric layer; and a third dielectric layer formed over at least a portion of the second metallic layer. At least one of the metallic layers is a subcritical metallic layer having discontinuous metallic regions. The subcritical metal layer includes copper, and optionally a second metal, such as silver.

An additional coated article comprises a substrate and a coating stack over at least a portion of the substrate. The coating stack comprises a first dielectric layer; at least one discontinuous metallic layer over the first dielectric layer; and a second dielectric layer over the discontinuous metallic layer. A further coated article comprises a substrate and a coating formed over at least a portion of the substrate. The coating comprises a first dielectric layer formed over at least a portion of the substrate and comprising a zinc oxide layer over a zinc stannate layer; a first, continuous metallic layer over the first dielectric layer; a first primer layer over the first continuous metallic silver layer, the first primer comprising titanium; a second dielectric layer over the first primer layer comprising a zinc stannate layer over a zinc oxide layer; a second, discontinuous metallic layer over the second dielectric layer comprising copper and optionally a second metal, such as silver; a second primer over the second discontinuous metallic layer; a third dielectric layer over the second primer layer and comprising a zinc oxide layer, a zinc stannate layer, and optionally another zinc oxide layer; a third continuous metallic layer over the third dielectric layer; a third primer layer comprising titanium over the third continuous metallic silver layer; a fourth dielectric layer comprising a zinc stannate layer over a zinc oxide layer over the third primer layer; and a protective coating comprising titanic over the fourth dielectric coating.

An architectural transparency of the invention comprises a substrate having a first dielectric layer formed over at least a portion of the substrate. A continuous metallic layer is formed over at least a portion of the first dielectric layer. A second dielectric layer is formed over at least a portion of the first metallic layer. A subcritical metallic layer is formed over at least a portion of the second dielectric layer such that the subcritical metallic layer forms discontinuous metallic regions, the subcritical metallic layer comprising copper and optionally a second metal, such as silver. A third dielectric layer is formed over at least a portion of the subcritical metallic layer. The metals of the continuous metallic layer and the subcritical metallic layer can be the same or different metals.

Another architectural transparency of the invention comprises a glass substrate with a first dielectric layer formed over at least a portion of the glass substrate. A continuous first metallic layer is formed over at least a portion of the first dielectric layer. A second dielectric layer is formed over at least a portion of the first metallic layer. A second metal layer (subcritical metallic layer) is formed over at least a portion of the second dielectric layer such that the subcritical metallic layer forms discontinuous metallic regions, the subcritical metallic layer comprises copper and optionally a second metal, such as silver. A third dielectric layer is formed over at least a portion of the subcritical metallic layer. A continuous third metal layer is formed over at least a portion of the third dielectric layer. A protective layer is formed over at least a portion of the third metallic layer. The metals of the continuous metallic layers and the subcritical metallic layer can be the same or different metals. A fourth dielectric layer is formed over at least a portion of the third metallic layer under the protective layer.

A further architectural transparency comprises a substrate with a first dielectric layer formed over at least a portion of the substrate. A continuous first metal layer is formed over at least a portion of the first dielectric layer. An absorbing layer is formed over at least a portion of the first metal layer. The absorbing layer comprises a first silicon nitride film, a metal layer formed over at least a portion of the first silicon nitride film, and a second silicon nitride film formed over the metal layer.

Another architectural transparency comprises a glass substrate with a first dielectric layer formed over at least a portion of the glass substrate. A continuous first metal layer is formed over at least a portion of the first dielectric layer. A first primer layer is formed over at least a portion of the first metal layer. The first primer layer comprises a multi-film layer. A second dielectric layer is formed over the first primer layer. A second continuous metal layer is formed over the second dielectric layer. A second primer layer is formed over the second metal layer. The second primer layer comprises a multi-film layer. The first and second primer layers can comprise a nickel-chromium alloy layer (such as Inconel) and a metal layer, such as titanium.

A coated article having a tinted appearance in reflection and/or transmission comprises a substrate, a first dielectric layer, a subcritical metallic layer having discontinuous metallic regions, an optional primer layer over the subcritical layer, and a second dielectric layer over the primer layer. The primer can comprise a nickel-chromium alloy. For example, the primer can comprise a multilayer primer having a first layer comprising a nickel-chromium alloy and a second layer comprising titania. Alternatively, the primer can comprise a zinc and tin material deposited as a metal and subsequently oxidized to form an oxide layer.

Another coated article having a tinted appearance in reflection and/or transmission comprises a substrate, a first dielectric layer, an absorbing layer, and a second dielectric layer over the absorbing layer. The absorbing layer can comprise at least one of a nickel-chromium alloy (such as Inconel), titanium nitride, cobalt chrome (stellite), or nickel chrome. A primer layer can be located over the absorbing layer. The primer layer can comprise titanium.

A method of making a coated article having a tinted appearance in reflection and/or transmission, wherein the article comprises a substrate, a first dielectric layer, a subcritical metallic layer having discontinuous metallic regions, an optional primer over the subcritical layer, and a second dielectric layer over the primer layer. The method includes selecting a metal for the subcritical metallic layer, wherein the metal is copper, selecting a primer material and thickness, and selecting dielectric material(s) and thickness to provide the coating with an absorbed color (e.g., tint) simulating the color of conventional tinted glass. The method optionally comprises selecting a second metal for the subcritical metallic layer, wherein the metal is applied to the substrate over the first dielectric layer, and the second metal is applied to the substrate over the metal.

