Disc heater and temperature control apparatus

1. Field of the Invention A disc heater is applied to a temperature control apparatus which controls a temperature of an object to be processed on at least one surface thereof. In the disc heater, wire-like heating elements are laid on a plate surface in a predetermined pattern and power feeding portions are disposed at ends of the wire-like heating elements. The pattern formed by the wire-like heating elements comprise a large number of arc portions disposed on a large number of concentric circles, and a surface area of the arc portions is 70% or greater, more preferably, 85 to 95% of a surface area of the entire pattern. With this feature, it is possible to effectively reduce the local excessively heated portion to the utmost, and to uniformly heat the entire heating surface, thus realizing an ideal topology pattern of the disc heater.