JP6039340B2 - microwave - Google Patents

Description

  The present invention relates to a microwave oven provided with an infrared sensor.

  A conventional microwave oven is disclosed in Patent Document 1. This microwave oven is provided with a main body having a heating chamber for opening the front and storing the food, and a door for opening and closing the front of the heating chamber. A magnetron for generating microwaves is provided in the main body. A microwave is supplied into the heating chamber by a magnetron to heat the cooked food.

  An opening is formed in the wall surface of the heating chamber, and an infrared sensor facing the heating chamber through the opening is provided. The temperature of the food is detected by the infrared sensor, and the output of the magnetron is varied according to the temperature of the food. Thereby, cooking without variation can be performed.

  However, according to the above-described conventional microwave oven, there is a case in which condensation generated by splashes or water vapor generated from the cooked food after the cooking is finished adheres to the surface of the infrared sensor. At this time, when the next cooking is started, infrared rays are absorbed by water droplets due to splashes or condensation, so that the measurement accuracy of the infrared sensor is lowered. Thereby, there was a problem that the exact temperature of the food could not be detected and good cooking could not be performed.

  In order to solve this problem, there is known a microwave oven that drives a blower fan disposed in a main body after cooking. The blower fan is disposed in a space communicating with the heating chamber through the opening, and is driven at a predetermined time to cool the magnetron. When the blower fan is driven after cooking is finished, the dynamic pressure in the space outside the heating chamber rises, and splashes and water vapor outflow from the opening are prevented. This prevents water droplets from adhering to the infrared sensor. The blower fan is driven only for a predetermined blowing period, and is stopped when the temperature of the food is lowered and no water vapor or splash is generated.

  Further, if the door is opened during the blowing period, it is determined that the food is taken out, and the blowing fan is stopped. Thereby, the blower fan can be stopped before the end of the long blowing period, and power saving of the microwave oven can be achieved.

JP 2001-304564 A (2nd to 4th pages, FIG. 1)

  However, according to the latter microwave oven, when the door is opened and closed during the air blowing period and the food is not taken out, splashes and condensation from the food adhere to the infrared sensor. For this reason, there was a problem that the case where the next dish cannot be made well still occurs.

  An object of this invention is to provide the microwave oven which can perform favorable cooking.

  In order to achieve the above object, the present invention includes a heating chamber for storing a cooked product and having an opening on a wall surface, a door for opening and closing the heating chamber, a magnetron for generating a microwave and heating the cooked product, An infrared sensor that faces the heating chamber through the opening and detects the temperature of the food, a door open / close detection unit that detects opening and closing of the door, and a space that communicates with the heating chamber through the opening An air blowing fan disposed inside, provided with an air blowing period for driving the air blowing fan after cooking is completed, and when the door is opened and closed within the air blowing period, the detection temperature of the infrared sensor before and after the door is opened and closed When the difference is larger than a predetermined value, the blower fan is stopped, and when the difference is small, the blower fan is in a driving state.

  According to this configuration, cooking is performed when the cooked food is stored in the heating chamber and the magnetron is driven. During cooking, the temperature of the food is detected by the infrared sensor, and cooking according to the temperature of the food is performed. When cooking is completed, the blower fan is driven for a predetermined blowing period. Thereby, the dynamic pressure in the space outside the heating chamber is increased, and water droplets are prevented from adhering to the infrared sensor through the opening. Further, when the door is opened and closed during the blowing period, the detection temperatures of the infrared sensors before and after opening and closing are compared. If the temperature difference before and after the door is opened and closed is greater than a predetermined value, it is determined that the food has been taken out, and the blower fan is stopped. If the temperature difference before and after the door opening / closing is smaller than a predetermined value, it is determined that the food remains, and the blower fan is continuously driven. The blower fan may be stopped when the door is opened, and may be re-driven when the temperature difference before and after opening and closing the door is smaller than a predetermined value.

  The present invention also includes a heating chamber that accommodates a cooked food and has an opening on the wall surface, a door that opens and closes the heating chamber, a magnetron that generates microwaves to heat the cooked food, and the opening. An infrared sensor that faces the heating chamber and detects the temperature of the food, a humidity sensor that detects humidity in the heating chamber, a door open / close detection unit that detects opening and closing of the door, and the opening through the opening. A blower fan arranged in a space communicating with the heating chamber, and providing a blower period for driving the blower fan after cooking, and stopping the blower fan when the door is opened in the blower period And when the humidity detected by the humidity sensor increases after closing the door, the air blowing fan is driven again.

  According to this configuration, cooking is performed when the cooked food is stored in the heating chamber and the magnetron is driven. During cooking, the temperature of the food is detected by the infrared sensor, and cooking according to the temperature of the food is performed. When cooking is completed, the blower fan is driven for a predetermined blowing period. Thereby, the dynamic pressure in the space outside the heating chamber is increased, and water droplets are prevented from adhering to the infrared sensor through the opening. Further, when the door is opened during the blowing period, the blowing fan is stopped, and when the door is closed, the humidity detected by the humidity sensor before and after the door is closed is compared. If the humidity after closing the door is not increased, it is determined that the food has been taken out, and the blower fan is kept stopped. If the humidity after closing the door increases before closing the door, it is determined that the food is not taken out, and the blower fan is driven again.

  Further, the present invention is characterized in that in the microwave oven having the above-described configuration, the cooking end time is determined based on the detection result of the humidity sensor.

  According to the present invention, in the microwave oven having the above-described configuration, the magnetron is disposed in the space and cooled by driving the blower fan.

  According to the present invention, the blower fan is stopped when the difference between the detected temperatures of the infrared sensors before and after opening and closing the door is larger than a predetermined value within the blowing period after the cooking is finished, and the blower fan is driven when it is small. . Thereby, when the food is taken out within the blowing period, the blowing fan can be stopped to save power. Moreover, when the food is not taken out, the blower fan is driven to prevent water droplets from adhering to the infrared sensor, and the next cooking can be performed satisfactorily.

  Further, according to the present invention, when the door is opened within the blowing period after the cooking is finished, the blowing fan is stopped, and when the humidity detected by the humidity sensor is increased when the door is closed than when the door is closed, the blowing fan is restarted. Driving. Thereby, when a foodstuff is taken out, a ventilation fan can be stopped and power saving can be achieved. Moreover, when the food is not taken out, the blower fan is driven to prevent water droplets from adhering to the infrared sensor, and the next cooking can be performed satisfactorily.

The perspective view which shows the microwave oven of 1st Embodiment of this invention. Front sectional drawing which shows the main-body part of the microwave oven of 1st Embodiment of this invention. The block diagram which shows the structure of the microwave oven of 1st Embodiment of this invention. The flowchart which shows operation | movement of the microwave oven of 1st Embodiment of this invention. The flowchart which shows operation | movement of the microwave oven of 2nd Embodiment of this invention.

<First Embodiment>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the microwave oven of the first embodiment. The microwave oven 1 includes a main body portion 2 having a heating chamber 3 for storing a cooked food, and a door 4 that pivots on the main body portion 2 to open and close the heating chamber 3. The door 4 is provided with a window portion 4a for visually recognizing the inside of the heating chamber 3. An operation panel 5 is provided on the upper portion of the main body 2.

  FIG. 2 is a front sectional view of the main body 2 of the microwave oven 1. A magnetron 6 that generates microwaves is disposed in a space 18 in the main body 2 that is lateral to the heating chamber 3. A blower fan 15 is disposed below the magnetron 6 in the space 18. By driving the blower fan 15, outside air flows into the space 18 from an inlet (not shown) that opens to the bottom surface of the main body 2, and flows out from an outlet (not shown) that opens to the back of the main body 2. Thereby, the magnetron 6 is cooled.

  A waveguide 7 that guides microwaves is provided below the heating chamber 3, and an antenna 8 is disposed in the waveguide 7. The antenna 8 is rotated by an antenna motor 8a, and the microwave is stirred and supplied uniformly to the heating chamber 3.

  An opening 3b is opened in the upper part of one side wall 3a of the heating chamber 3, and an exhaust port 3c is opened in the back wall. The opening 3b and the exhaust port 3c are formed by small holes through which microwaves do not leak. An infrared sensor 13 mounted on the substrate 13a is disposed above the space 18. The infrared sensor 13 faces the heating chamber 3 through the opening 3b and detects the temperature of the food.

  FIG. 3 is a block diagram showing the configuration of the microwave oven 1. The microwave oven 1 includes a control unit 10 that controls each unit. The control unit 10 is connected to the magnetron 6, the antenna 8, the blower fan 15, the storage unit 16, the operation panel 5, the door opening / closing sensor 12, the infrared sensor 13, and the humidity sensor 14. The control unit 10 has a built-in timer for measuring time.

  The storage unit 16 includes a RAM and a ROM, and stores an operation program of the microwave oven 1, a cooking menu database, and the like, and temporarily stores a calculation result by the control unit 10. The door opening / closing sensor 12 detects opening / closing of the door 4 (see FIG. 1). The humidity sensor 14 is disposed in an exhaust duct (not shown) derived from the exhaust port 3c (see FIG. 2), and detects the humidity in the heating chamber 3.

  FIG. 4 is a flowchart showing the operation of the microwave oven 1. When the door 4 is opened to store the food, the power is turned on and the operation program is started. In step # 11, the cooking menu is selected and the process waits until the start of cooking is instructed. When the start of cooking is instructed, it is determined whether or not the door 4 is closed in step # 12. When the door 4 is closed, the process proceeds to step # 13.

  In step # 13, the magnetron 6 and the antenna motor 8a are driven. In step # 14, the blower fan 15 is driven. The microwave generated by the magnetron 6 is guided through the waveguide 7, stirred by the antenna 8, and supplied to the heating chamber 3. Thereby, the food in the heating chamber 3 is cooked. Further, the magnetron 6 is cooled by the blower fan 15.

  In step # 15, the temperature of the food is detected by the infrared sensor 13, and the humidity in the heating chamber 3 is detected by the humidity sensor 14. In step # 16, it is determined whether or not the humidity of the heating chamber 3 detected by the humidity sensor 14 has reached a predetermined end humidity. When the heating chamber 3 has not reached the end humidity, the process proceeds to step # 17, and the output of the magnetron 6 is adjusted according to the temperature of the food. Thereby, the amount of heating can be varied according to the progress of cooking, and good cooking can be performed. And cooking progresses by repeating step # 15- # 17.

  When the inside of the heating chamber 3 reaches the end humidity due to the steam generated from the cooked food, it is determined that the cooking is finished, and the process proceeds to step # 18. In step # 18, the magnetron 6 and the antenna motor 8a are stopped. The end of cooking may be determined based on the temperature detected by the infrared sensor 13.

  In step # 21, the temperature T 1 is detected by the infrared sensor 13 and stored in the storage unit 16. In step # 22, it is determined whether or not the door 4 has been opened. If the door 4 has not been opened, it is determined in step # 23 whether or not the air blowing period for a predetermined time (30 minutes in the present embodiment) has elapsed after cooking. Although the ventilation period is set by time, the period during which the temperature detected by the infrared sensor 13 is lowered to a predetermined temperature may be set as the ventilation period.

  Steps # 21 to # 23 are repeated when the blowing period has not elapsed after cooking. At this time, the blower fan 15 is continuously driven, and the water droplets on the infrared sensor 13 are prevented from adhering. When the blowing period ends, the process proceeds to step # 26 based on the determination in step # 23, and the blowing fan 15 is stopped. Thereby, the operation program ends.

  If it is detected in step # 22 that the door 4 has been opened, the process proceeds to step # 24 and waits until the door 4 is closed. When the door 4 is closed, the temperature T2 is detected by the infrared sensor 13 in step # 25. In step # 26, it is determined whether or not the difference (T1-T2) between the temperatures T1 and T2 detected in steps # 21 and # 25 is greater than a predetermined value Ta.

  When the difference (T1−T2) between the temperatures T1 and T2 is equal to or less than the predetermined value Ta, it is determined that the cooked food remains in the heating chamber 3. Thereby, it transfers to step # 21, the drive state of the ventilation fan 15 is continued, and steps # 21- # 23 are repeated. If the difference between the temperatures T1 and T2 (T1-T2) is greater than the predetermined value Ta, it is determined that the cooked food in the heating chamber 3 has been taken out, and the blower fan 15 is stopped in step # 26. Thereby, the operation program ends.

  According to the present embodiment, the blower fan 15 is stopped when the difference (T1-T2) in the detection temperature of the infrared sensor 13 before and after opening and closing of the door 4 is larger than the predetermined value Ta within the blowing period after the cooking is finished, and is small Sometimes the blower fan 15 is in a driving state. Thereby, when the food is taken out within the blowing period, the blower fan 15 can be stopped to save power. Moreover, when the food is not taken out, the blower fan 15 is driven to prevent water droplets from adhering to the infrared sensor 13 and the next cooking can be performed satisfactorily.

  Note that the blower fan 15 may be stopped when the door 4 is opened in step # 22, and the blower fan 15 may be redriven to be in a drive state when the process proceeds to step # 21 as determined in step # 26.

  Further, since the magnetron 8 is cooled by driving the blower fan 15, it is not necessary to provide a separate blower fan for preventing water droplets of the infrared sensor 13, and an increase in cost of the microwave oven 1 can be suppressed.

Second Embodiment
Next, the microwave oven 1 of 2nd Embodiment is demonstrated. The microwave oven 1 of the present embodiment is configured in the same manner as the first embodiment, and the operation program is different from that of the first embodiment. FIG. 5 is a flowchart showing the operation of the microwave oven 1 according to this embodiment. Steps # 11 to # 18 are the same as those in FIG.

  When cooking is completed and the magnetron 6 and the antenna motor 8a are stopped in step # 18, the process proceeds to step # 31. In step # 31, it is determined whether or not the door 4 has been opened. If the door 4 has not been opened, it is determined in step # 32 whether or not the blowing period (30 minutes) has elapsed after the cooking has ended. A period during which the temperature detected by the infrared sensor 13 is lowered to a predetermined temperature may be set as a blowing period.

  Steps # 31 and # 32 are repeated when the blowing period has not elapsed after cooking. At this time, the blower fan 15 is continuously driven, and the water droplets on the infrared sensor 13 are prevented from adhering. When the blowing period ends, the process proceeds to step # 39 based on the determination in step # 32, and the blowing fan 15 is stopped. Thereby, the operation program ends.

  If it is detected in step # 31 that the door 4 has been opened, the blower fan 15 is stopped in step # 33. In step # 34, the humidity H1 is detected by the humidity sensor 14 and stored in the storage unit 16. In step # 35, the process waits until the door 4 is closed. When the door 4 is closed, the humidity H2 is detected by the humidity sensor 14 in step # 36.

  In step # 37, it is determined whether or not the humidity H2 detected in step # 36 is higher than the humidity H1 detected in step # 34. When the door 3 is opened, the water vapor in the heating chamber 3 flows out, so that the humidity decreases. When the food remains when the door 3 is closed, the humidity increases due to the water vapor generated from the food. For this reason, when the humidity H2 increases from the humidity H1, it is determined that the cooked food remains in the heating chamber 3. As a result, the blower fan 15 is re-driven in step # 38, and steps # 31 and # 32 are repeated. When the humidity H2 is not higher than the humidity H1, it is determined that the cooked food in the heating chamber 3 has been taken out, and the operation program ends.

  According to this embodiment, when the door 4 is opened within the air blowing period after the cooking is finished, the air blowing fan 15 is stopped, and when the door 4 is closed, the humidity detected by the humidity sensor 14 is increased compared to before the door 4 is closed. The blower fan 15 is re-driven. Thereby, when the food is taken out within the blowing period, the blower fan 15 can be stopped to save power. Moreover, when the food is not taken out, the blower fan 15 is driven to prevent water droplets from adhering to the infrared sensor 13 and the next cooking can be performed satisfactorily.

  Moreover, since the end time of cooking is determined based on the detection result of the humidity sensor 14, it is not necessary to provide a separate humidity sensor for preventing water droplets of the infrared sensor 13, and an increase in the cost of the microwave oven 1 can be suppressed. .

  According to the present invention, it can be used for a microwave oven provided with an infrared sensor.

DESCRIPTION OF SYMBOLS 1 Microwave oven 2 Main body part 3 Heating chamber 3b Opening part 3c Exhaust port 4 Door 5 Operation panel 6 Magnetron 7 Waveguide 8 Antenna 10 Control part 12 Door open / close sensor 13 Infrared sensor 14 Humidity sensor 15 Blower fan

Claims (3)

  A heating chamber that houses the food and has an opening on the wall, a door that opens and closes the heating chamber, a magnetron that generates microwaves to heat the food, and the heating chamber through the opening. An infrared sensor that detects the temperature of the cooked food, a humidity sensor that detects the humidity in the heating chamber, a door open / close detection unit that detects opening / closing of the door, and the heating chamber communicates with the heating chamber via the opening. A blower fan disposed in the space, and providing a blower period for driving the blower fan after cooking, and stopping the blower fan when the door is opened during the blower period. The microwave oven, wherein the blower fan is re-driven when the humidity detected by the humidity sensor is increased after closing compared to before the door is closed. The microwave oven according to claim 1 , wherein cooking end time is determined based on a detection result of the humidity sensor. The microwave oven according to claim 1 or 2 , wherein the magnetron is disposed in the space and cooled by driving the blower fan.

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