Patent ID: 7075401

Claim:
A small-diameter ignition coil comprising: a center core; a primary coil that is arranged on an outer circumferential side with respect to the center core; a secondary coil that is arranged on the outer circumferential side with respect to the center core; a thin film tube that has a cylindrical shape, the thin film tube arranged on an outer circumferential side with respect to one of the primary coil and the secondary coil that is arranged on an outer circumferential side with respect to the other of the primary coil and the secondary coil; a first spool that has a cylindrical shape on which the one of the primary coil and the secondary coil is wound; and an electrically insulative resin filled in a gap formed between the thin film tube and the one of the primary coil and the secondary coil, wherein the thin film tube is thermally resistive and electrically insulative, the first spool has at least one collar portion that opposes the thin film tube in a radial direction of the first spool, the thin film tube forms a cylindrical wall that accommodates the center core, the primary coil, the secondary coil, and the electrically insulative resin, and the thin film tube has a wall thickness that is equal to or less than 0.35 mm.