US Patent 11867410 Electric heater and cooking appliance having same

An electric heater includes a substrate; a first plane heating element disposed on a surface of the substrate; and a second plane heating element disposed on the surface of the substrate so as to be located outside the first plane heating element. The first plane heating element includes a first pattern portion having a start point and an end point, and a pair of first electrode portions connected to the first pattern portion. The second plane heating element includes a second pattern portion that surrounds a portion of an outer circumference of the first pattern portion, has a start point and an end point, and has an opening portion at one side thereof; and a pair of second electrode portions connected to the second pattern portion.