Patent ID: 6013907
Filing Date: 2000-01-11
Classification: H05B

Abstract:
In a microwave oven equipped with a thermopile including light condensing means for condensing an infrared ray from at least one of food and a turntable within the microwave oven, a thermopile sensor module for generating a voltage based on output from the light condensing means, and an amplifier for amplifying the voltage generated by the thermopile sensor module to a predetermined level, and an analog/digital converter for converting the voltage signal from the amplifier into a digital voltage signal, and a microcomputer for processing a voltage signal from the analog/digital converter and for controlling an energy supplied from the magnetron to the food placed in a heating chamber based on an internally provided thawing program, said microcomputer comprising:a voltage signal sampling unit for periodically reading a digital signal from the analog/digital converter;a voltage signal processing unit for converting the digital signal periodically read by the voltage signal sampling unit into a temperature, eliminating a noise from the converted temperature, and computing a maximum value, a minimum value, and a mean value of the temperature corresponding to a magnetron on/off period;a temperature data sampling unit for sampling the maximum value, the minimum value, and the mean value computed by the voltage signal processing unit;a magnetron turn-on ratio computation and abnormal operation judging unit for computing an optimum magnetron on/off time for a magnetron on/off period based on the data sampled by the temperature data sampling unit, determining the thawing completion time so that the thawing operation is terminated at an optimum time, and terminating the thawing operation when an abnormal operation is detected based on a state of the food; anda magnetron on/off switch controller for outputting a control signal to the magnetron on/off switch in accordance with an output from the magnetron turn-on time ratio computation and abnormal operation judging unit.