Abstract: A self regulating heating device includes a first layer made of an electrically insulating material. The first layer is thin and flexible. First and second buses spaced from each other are connected to the first layer. A resistive layer electrically connects the first and second buses. The resistive layer has a higher electrical resistance than the second layer. The resistive layer experiences a positive temperature coefficient (PTC) effect when heated. A solar active layer is connected to the first layer. The solar active layer is electrically connected to the first and second buses. The solar active layer converts light into electrical energy to apply a voltage across the first and second buses.

Abstract: The present invention is directed to a self regulating heater including a first layer made of a thin and flexible electrically insulating material. A second electrically conductive layer includes first and second buses spaced from each other. A third resistive layer electrically connects the first and second buses. The third layer has a higher electrical resistance than the second layer. The third layer experiences a positive temperature coefficient (PTC) effect when heated. A fourth interface layer directly connected to at least one of the second electrically conductive layer and the third resistive layer directly engages skin of a patient when the heater is attached to the patient. A combined thickness of the first layer, the second conductive layer, the third resistive layer and the fourth layer may be between 5 mil and 20 mil.

Abstract: A seat cushion includes a support member. A cover encloses the support member. A self-regulating heating device extends between the support member and an upper portion of the cover.