| 摘要 |
PURPOSE:To permit to measure the temperature of a substance under the optimum condition at all times by a method wherein the frequency of opening and closing of a shutter is changed to regulate the amount of radiation of infrared-ray projected into the sensor. CONSTITUTION:The shutter 13, interposed between an opening 11 at the ceiling of a heating chamber 3 and the infrared-ray sensor 12, is operated in accordance with the command of a control unit 14 and intercepts periodically a path of radiation energy from a food into the infrared-ray sensor 12 through the opening 11. The infrared-ray sensor 12 and the oscillating circuit 23 output the oscillating pulse of a frequency in accordance with the magnitude of the inputs thereof to the terminal R4 of a omicrocomputer 15. The microcomputer 15 detects the temperature condition of the surface of substance by counting the number of oscillating pulse. The opening and closing signal of the shutter 13 is outputted from the terminal R5 of the microcomputer 15 and the shutter obstructs the view of sensor 12 in accordance with the output frequency of the computer 15. Thus, the microcomputer 15 detects the temperature of the food from the opening and closing frequency of the shutter 13 and the value of input frequency of the same and controls at that time the output level of the terminal R2 or the same R3 to control a magnetron circuit 18. |
