Induction heating cooking apparatus

Claim 1

An induction heating cooking apparatus comprising a flat pan supporting plate made of a heat-resistant dielectric material for supporting a pan thereon, said plate having upper and lower surfaces; a heating coil for induction heating of said pan, said heating coil being positioned under said pan supporting plate; a power source for supplying a high frequency current to said heating coil; a first touch pad for producing a first signal to effect turning on of said power source upon being touched with a finger; a second touch pad for producing a second signal to effect turning off of said power source upon being touched with a finger; a third touch pad for producing a third signal to effect setting of a power level of said power source to a predetermined level; each of said first, second and third touch pads constituting a capacitor-pair formed by a first electrode attached to the upper surface of said pan supporting plate and second and third electrodes respectively mounted on the lower surface of said pan supporting plate, the capacitance of the capacitor-pair being varied when the first electrode is touched; a control circuit connected to said first, second and third touch pads and said power source for controlling the supply of said high frequency current from said power source in response to said first, second and third signals from said first, second and third touch pads; a first guard ring made of a conductive material formed on the upper surface of said pan supporting plate enclosing said first electrodes of said first, second and third touch pads, said first guard ring being connected to said first electrode of said second touch pad; and a second guard ring made of a conductive material formed on the upper surface of said pan supporting plate enclosing said first guard ring, said second guard ring being grounded.