CPC F24C 7/083 (2013.01) [F24C 7/067 (2013.01); H05B 3/03 (2013.01); H05B 2203/005 (2013.01)] | 12 Claims |
1. An electric heater comprising:
a substrate; and
a plane heating element disposed on one surface of the substrate,
wherein the plane heating element includes:
a pattern portion including a start point and an end point, which are located at an outermost side of the pattern portion,
wherein the pattern portion includes:
a plurality of tracks having an arc shape, which are spaced apart from each other and are formed to have a length increasing from an innermost side to the outermost side of the pattern portion, and
a plurality of bridges connecting the plurality of tracks in series,
wherein the plurality of bridges are formed on both sides of the pattern portion with respect to a reference line passing through a center of the pattern portion, and a pair of bridges is a bridge on one side facing a bridge on an other side of the pattern portion, and
wherein, for each two adjacent pairs of bridges, a gap between a pair of bridges and a gap between an adjacent pair of bridges have a width increasing from the innermost side to the outermost side of the pattern portion.
|