Method and apparatus for magnetic induction heating using radio frequency identification of object to be heated

Abstract

A temperature-regulating induction heating system is provided which comprises an induction heater ( 20 ) having apparatus ( 36, 38, 40 ) for receiving RFID transmissions and an induction heatable object ( 22 ) with an RFID tag ( 50 ). The heater ( 20 ) includes a component ( 28 ) for generating a magnetic field, control circuitry including a microprocessor ( 32 ) coupled with the component ( 28 ) for selectively initiating and terminating generation of a magnetic field; the receiving apparatus ( 36, 38, 40 ) provides information to the microprocessor ( 32 ) causing initiation of a heating algorithm for the object ( 22 ). In preferred forms, the tag ( 50 ) and apparatus ( 36, 38, 40 ) are designed for two-way information transfer, thereby permitting continuous updating of the information carried by tag ( 50 ). In this way, if induction heating of the object ( 20 ) is interrupted, it may be resumed to nevertheless achieve a desired regulation temperature. Advantageously, the RFID tag ( 50 ) and apparatus ( 36, 38, 40 ) operate during intermittent interruption of the primary magnetic field of the heater ( 20 ) to eliminate transmission interference. The tag ( 50 ) may be equipped with one or more thermal switches ( 100, 104, 106 ) to provide better temperature control.

1 . An RFID tag comprising transmission circuitry and an antenna operably coupled with the transmission circuit, with a switch operably coupled with at least one of said transmission circuit and antenna, said switch being switchable between circuit make and circuit break orientations in response to an external condition experienced by the switch, in order to alter the operation of the RFID tag.  
     
     
         2 . The tag of  claim 1 , said switch being a thermal switch switchable between said orientations in response to the temperature experienced by the thermal switch.  
     
     
         3 . The tag of  claim 1 , said switch operably coupled to said antenna in order to short said antenna in one of said switch orientations.  
     
     
         4 . The tag of  claim 1 , including a pair of series-connected switches operably coupled with at least one of said transmission circuit and antenna.  
     
     
         5 . The tag of  claim 4 , said switches operably coupled to said antenna.