Abstract A novel silk screen, a novel process of making it, and a novel use in the technology of heating flat bodies such as automobile and factory windows. The new screen is characterized by slits of differential width, depth, or both which permit the deposit of lines of differential section. This has a special significance when the lines are composed of electrical conductors of resistance type of which the resistivity of a part is determined by its section. The process involves a method of making the new type of silk screen which is extremely flexible and permits the construction of screens, the slits of which are differential as to width and differential as to thickness. The process has been achieved by a novel process which relies upon basic techniques already known to the silk screen art, such as the making of emulsions of proper conductivity for heating lines, the technique of preparing the emulsions, and the technique of dissolving those portions which must be removed to form the slits constituting the design. The invention also involves the novel windows which bear designs of differential resitivity producing different temperatures in different parts. These advantages are particularly important in the automotive field but are equally so in factories where overhead windows can be kept clear to furnish light even during snowy weather. Other objects, novelties, and advantages of the invention will be apparent after the reading of this specification.
A thermal window comprising a smooth-surfaced transparent glass sheet, a plurality of opaque electrically conductive resistance lines of hardened metallic ink adhered to a surface of said sheet, at least some of said lines being of uniform composition along tHe length thereof and having a cross-section which is smaller over a common viewing portion of the length thereof between their ends than over the end portions thereof for increased heating within said viewing portion, said at least some lines extending substantially parallel to each other and having a width and being separated one from the other by a distance so as not to obstruct visibility through said glass sheet, and electrically conductive resistance lines adhered to said surface and connecting ends of said plurality of lines into a single circuit.
Claim 2
Dependent Claim
130 words
A thermal window comprising a smooth-surfaced transparent glass sheet, a plurality of opaque electrically conductive resistance lines of hardened metallic ink adhered to a surface of said sheet, at least some of said lines being of uniform composition along tHe length thereof and having a cross-section which is smaller over a common viewing portion of the length thereof between their ends than over the end portions thereof for increased heating within said viewing portion, said at least some lines extending substantially parallel to each other and having a width and being separated one from the other by a distance so as not to obstruct visibility through said glass sheet, and electrically conductive resistance lines adhered to said surface and connecting ends of said plurality of lines into a single circuit.
Claim 3
Dependent Claim
21 words
A thermal window according to claim 1 wherein said at least some resistance lines consist essentially of said hardened metallic ink.
Claim 4
Dependent Claim
39 words
A thermal window according to claim 1 wherein at the portions of smaller cross-section thereof said at least some lines are narrower in dimension parallel to the surface of said sheet than at the portions of larger cross-section thereof.
Claim 5
Dependent Claim
40 words
A thermal window according to claim 1 wherein at the portions of smaller cross section thereof said at least some lines are thinner in dimension perpendicular to the surface of said sheet than at the portions of larger cross-section thereof.