Patent ID: 7183524

Claim:
A heated blanket comprising: a first pliable outer layer configured for durable protection in an outdoor environment; a pliable multi-layered electrical heating element positioned on one side of the first outer layer, the multi-layered electrical heating element having at least two resistive elements configured to convert electrical energy to heat energy, wherein the pliable multi-layered electrical heating element is configured to produce about 9 watts per foot with a total wattage not exceeding about 2400 watts; the pliable multi-layered electrical heating element comprising: a thermal reflection layer configured to reflect heat radiated from the resistive elements back towards the resistive elements; a first separation layer disposed between the thermal reflection layer and the resistive elements, the first separation layer configured to prevent direct contact between the thermal reflection layer and the resistive elements; a second separation layer disposed such that the resistive elements are positioned between the first separation layer and the second separation layer, the second separation layer configured to prevent direct contact between the resistive elements and a surface in contact with the pliable multi-layered electrical heating element; and an adhesive disposed between the first separation layer and the second separation layer, the adhesive and separation layers configured to conduct thermal energy from the resistive elements to the planar heat spreading element by way of the adhesive; a planar heat spreading element in contact with the multi-layered electrical heating element and configured to draw the heat energy out of the multi-layered electrical heating element and evenly distribute the heat energy over a substantial surface area of the first outer layer; and at least one electric power coupling connected to the pliable multi-layered electrical heating element to supply electrical power.