Patent attributes
A heater includes an aluminum nitride base having equal to or less than 1% impurities, particularly one embodiment having none of polybrominated biphenyl, polybrominated diphenyl ether, hexabromocyclododecane, polyvinyl chloride, chlorinated paraffin, phthalate, cadmium, hexavalent chromium, lead, and mercury. At least one resistive trace of silver and palladium overlies the base as does a conductor of silver and platinum or palladium that electrically connects to the resistive trace to apply an external voltage to the resistive trace for heating thereof. At least four, but optionally five, layers of glass overlie the resistive trace and part of the conductor. A first two consecutive layers of the glass layers define a first glass having a solid content of more than 65% and a viscosity of 100 Pa·s or less. The following two or three consecutive layers of the five layers define a second glass dissimilar to the first.
