Patent ID: 8263202

Claim:
A film based heating device comprising: A) a base film having a base film inner surface and a base film outer surface, said base film comprising: a) a base film aromatic polyimide in an amount from 55 to 90 weight percent based upon the total weight of said base film, b) a base film electrically conductive filler in an amount from 10 to 45 weight percent based upon the total weight of said base film; B) a first laminate comprising: a) a first laminate adhesive layer having a first laminate adhesive layer inner surface bonded to said base film inner surface and a first laminate adhesive layer outer surface, said first laminate adhesive layer containing: i. 55 to 90 weight percent of a first laminate adhesive layer thermoplastic polyimide, wherein 70 to 100 mole percent of said first laminate adhesive layer thermoplastic polyimide is derived from at least one aromatic diamine and at least one aromatic dianhydride, based upon the total weight of said first laminate adhesive layer, ii. 10 to 45 weight percent of a first laminate adhesive layer electrically conductive filler based upon the total weight of said first laminate adhesive layer, b) a first laminate metal foil having: i. a first laminate metal foil inner surface bonded to said first laminate adhesive layer outer surface; and ii. a first laminate metal foil outer surface, said first laminate metal foil having a thickness from 5 to 200 microns; C) a second laminate comprising: a) a second laminate adhesive layer having a second laminate adhesive layer inner surface bonded to said base film inner surface and a second laminate adhesive layer outer surface, said second laminate adhesive layer containing: i. 55 to 90 weight percent of a second laminate adhesive layer thermoplastic polyimide, wherein 70 to 100 mole percent of said first laminate adhesive layer thermoplastic polyimide is derived from at least one aromatic diamine and at least one aromatic dianhydride, based upon the total weight of said second laminate adhesive layer, ii. 10 to 45 weight percent of a second laminate adhesive layer electrically conductive filler based upon the total weight of said second laminate adhesive layer, b) a second laminate metal foil having: i. a second laminate metal foil inner surface bonded to said second laminate adhesive layer outer surface; and ii. a second laminate metal foil outer surface, said second laminate metal foil having a thickness from 5 to 200 microns; wherein at least a portion of said first laminate and at least a portion of said second laminate are spaced apart and connected to each other by at least a portion of said base film.