Solar load reduction panel with controllable light transparency

A multi-element, laminated glazing unit which is substantially transparent to visible light in at least one selectable condition and substantially non-transparent in a second selectable condition, the glazing unit comprising:

• electro-active means for controlling transparency to visible light, the electro-active means comprising (i) first and second electrodes sandwiching between them (ii) a layer of electro-active material which is controllably switchable from the substantially transparent condition to the substantially non-transparent condition by selected application of electrical potential across the electrodes, and (iii) first and second flexible, substantially inextensible polymeric layers sandwiching the electrodes and electro-active material between them, wherein the electrodes are sputter coated, one each, onto an inward surface of a corresponding one of the inextensible polymeric layers;
• first and second substantially transparent, substantially self-supporting plys sandwiching between them said electro-active means;
• a first laminating layer of flexible polymeric material mediate the electro-active means and the first substantially self-supporting ply, and a second laminating layer of flexible polymeric material laminating the electro-active means to the second substantially self-supporting ply;
• and
• a Fabry-Perot interference filter for reducing infrared light energy transmitted through the glazing unit, the interference filter comprising a film stack sputter coated onto a surface of the first ply, mediate the first ply and the first laminating layer, the film stack including, in order, at least a first zinc oxide film adjacent the first ply, a first silver metal film, a second zinc oxide film, a second silver metal film and a dielectric film adjacent the first laminating layer, the first laminating layer laminating the first polymer layer to the film stack on the surface of the first ply.

A laminated window which is substantially transparent to visible light in at least one selectable condition and substantially translucent in a second selectable condition, the laminated window comprising:

• electro-active means substantially coextensive with the laminated window for controlling the amount of visible light transmitted through the laminated window, the electro-active means having indium-tin oxide electrodes sandwiching between them a layer of liquid crystal material which is controllably switchable from the substantially transparent condition to the substantially translucent condition by selected application of electrical potential across the electrodes, and polyethylene terephthalate layers sandwiching between them the electrodes and the liquid crystal material, the indium-tin oxide electrodes being continuous sputter coated films, one on each of the polyethylene terephthalate layers;
• first and second glass plys sandwiching the electro-active means between them;
• an SLR film stack sputter coated onto a surface of the first glass facing the electro-active means, the SLR film stack including a zinc oxide film immediately adjacent the glass ply, a silver metal film over the zinc oxide film, a second zinc oxide film over the silver metal film, a second silver metal film over the second zinc oxide film and a film adjacent the polyvinyl butyral layer which is selected from (i) a zinc oxide film with a chromium oxide adhesion promoting film immediately adjacent to the polyvinyl butyral and (ii) a tantalum pentoxide film;
• and
• a first polyvinylbutyral layer laminating the electro-active means to the SLR film stack, and a second polyvinylbutyral layer laminating the electro-active means to the second glass ply.

A laminated glazing unit which is substantially transparent to visible light in at least one selectable condition, the glazing unit comprising:

• a first ply which is substantially transparent, substantially inextensible and substantially self-supporting;
• electro-active means for controlling the amount of visible light transmitted through the glazing unit, the electro-active means comprising (i) first and second flexible, substantially inextensible polymer layers, each having an inward surface facing the other, (ii) first and second electrodes on the inward surface of the first and second polymer layers, respectively, and (iii) a layer of electro-active material sandwiched between the electrodes, the electro-active material being controllably switchable from a first condition substantially transparent to visible light to a second, less transparent condition by selected application of electrical potential across the electrodes;
• a Fabry-Perot interference filter for reducing infrared light energy transmitted through the glazing unit, the interference filter comprising a film stack sputter coated onto a surface of the first ply, mediate the first ply and the first laminating layer, the film stack including, in order, at least a first zinc oxide film adjacent the first ply, a first silver metal film, a second zinc oxide film, a second silver metal film and a dielectric film adjacent the first laminating layer,
• a first laminating layer of flexible polymeric material laminating the interference filter on the surface of the first ply to an outward surface of the first polymer layer of the electro-active means;
• and
• electrical heating means for passing an electrical current through the film stack of the Fabry-Perot interference filter to electrically heat the windshield, the film stack being substantially electrically isolated from the electro-active means.

An electrically heated, laminated motor vehicle windshield having a laterally extending upper edge, a laterally extending lower edge and right side and left side edges, the windshield comprising:

• electro-active means extending laterally across an upper portion of the windshield for controlling the amount of visible light transmitted through the upper portion;
• an electrically conductive SLR film stack on, and substantially coextensive with, a laminated surface of a substantially inextensible ply of the windshield;
• and
• electrical heating means for passing an electrical current through the electrically conductive SLR film stack, the electrically heated windshield and the electrically conductive SLR film stack being effectively electrically isolated from the electro-active means.