Heated dome window

Claim 1

Transparent dome means comprising; a domical segment of transparent material of practically uniform thickness having inner and outer surfaces; a first electrically conductive coating, relatively thin and transparent, and covering substantially all of one of said surfaces, except for a relatively narrow peripheral area; said coating being separated into a plurality of elongated heating panels of relatively large area and a pair of relatively smaller side segments; a second electrically conductive coating on said one of said surfaces substantially filling said peripheral area and having discrete portions thereof in electrical contact with certain edges of said heating panels such that said panels are electrically connected in series; means including a temperature responsive solid state switching device for causing a flow of electrical current serially through said panels when ambient temperature prevails below a selected value and to block the flow of current when ambient temperature prevails above said selected value; said first and second coatings in combination constituting an effective shield against penetration of the transparent material by radio frequency radiation; and an antireflectance coating on the other of said surfaces.