Abstract An electrically heated transparent panel is described for a laminated safety glass window construction having a clear polymer inner layer with a pattern of wrinkled resistance wires oriented in a three-dimensional non-parallel random fashion so as to reduce glare from the wires when the window is used in automotive and other type vehicles. The individual resistance wires are partially embedded in the polymer sheet by a technique utilizing shrinkage of a thermoplastic polymer from its original dimensions when heated to an elevated temperature together with having the individual wires change configuration when relaxed from tension forces on the wire when first assembled with the polymer sheet. An improved form of bus-bar electrode means are connected at each end of the individual resistance wires by heat-bonding directly to the thermoplastic polymer sheet to provide the composite panel which can thereafter be handled and assembled by conventional further heat-bonding as the inner layer of a laminated safety glass construction.
In a composite sheet member for a laminated safety glass construction which comprises a layer of transparent thermoplastic polymer which has been heat-shrunk from its original dimensions by heating to an elevated temperature having partially embedded in one major surface a plurality of wrinkled resistance wires which lie in closely spaced relationship and are oriented with respect to one another in non-parallel random fashion so that portions of said individual resistance wires protrude from said major surface of the thermoplastic polymer layer, and bus-bar electrode means connected at each end of the individual resistance wires, the improvement wherein said bus-bar electrode means consist of a thin foil strip having a segmented construction which is secured by heat-bonding directly to the thermoplastic polymer layer at each end of the individual resistance wires with a continuous foil strip of greater width and thickness which overlays the subjacent segmented strip and is also heat-bonded directly to the thermoplastic polymer layer at each end of said individual resistance wires, and wherein the individual resistance wires are positioned between said continuous foil strip and the subjacent segmented strip so that portions of the segmented foil strip partially envelops said individual resistance wires and there is physical and electrical contact between said foil strips.
Claim 2
Dependent Claim
208 words
In a composite sheet member for a laminated safety glass construction which comprises a layer of transparent thermoplastic polymer which has been heat-shrunk from its original dimensions by heating to an elevated temperature having partially embedded in one major surface a plurality of wrinkled resistance wires which lie in closely spaced relationship and are oriented with respect to one another in non-parallel random fashion so that portions of said individual resistance wires protrude from said major surface of the thermoplastic polymer layer, and bus-bar electrode means connected at each end of the individual resistance wires, the improvement wherein said bus-bar electrode means consist of a thin foil strip having a segmented construction which is secured by heat-bonding directly to the thermoplastic polymer layer at each end of the individual resistance wires with a continuous foil strip of greater width and thickness which overlays the subjacent segmented strip and is also heat-bonded directly to the thermoplastic polymer layer at each end of said individual resistance wires, and wherein the individual resistance wires are positioned between said continuous foil strip and the subjacent segmented strip so that portions of the segmented foil strip partially envelops said individual resistance wires and there is physical and electrical contact between said foil strips.