JPS587790A - Electronic range - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microwave oven, and more particularly, to a microwave oven that uses a gas sensor to automatically determine when to finish cooking food.

Conventionally, a microwave oven that uses a sensor to automatically determine the finish of food cooking is equipped with multiple keys corresponding to the type of cooking, and a button 1 for each key, as shown in Figure 1. The cooking finishing temperature was preset. For example, the set temperature for the key KIK for heating items 11 side dishes and Imono is 70-80t1 for the key KIK for heating items 2 and sake can is 50-60°0, and the setting temperature for the key L for preparation and spinach. Set temperature is 10G
'O near O, etc. The user selects and sets the appropriate key on the operation panel according to the food to be cooked, and then presses the heating key to start cooking and heating.

However, in such a conventional example, the user has to select and display the key according to the food to be cooked, and if the selection is incorrect, the result of the cooking will be inappropriate. There is a high rate of incorrect presses, such as an increase in the number of buttons, and it becomes difficult to judge which button to press when cooking a dish without the cooking name written on the key top.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a microwave oven that is extremely convenient and has a simple configuration on the operation panel, requiring only one "auto cooking" key to be pressed.

FIG. 2 shows an external front view of an embodiment of the present invention. An "automatic heating" key 2 and a heating key 6 are arranged on the operation panel 1. Note that it is also possible to have one key 2 and one key 6.

FIG. 3 shows a sectional view of an embodiment of the present invention. A blower 5 is provided on one side of the open 4, and a gas sensor 7 and a thermistor 8 are provided at an exhaust port 6 on the other side.

The resistance value of the gas sensor 7 changes depending on the concentration of exhaust gas generated from the food, and the resistance value of the thermistor 8 changes depending on the temperature of the exhaust gas that increases as the food is heated. In the figure, 9 is a magnetron that emits microwaves, and 10 is a turntable on which food is placed.

FIG. 4 shows a circuit diagram of an embodiment of the present invention. gas sensor 7
is connected to the DC power supply 11 via the load resistor ILI11, the thermistor 8 is connected to the DC power supply 11 via the load resistor RL, and the terminal voltage G of the gas sensor 7 and the terminal voltage T of the thermistor 8 are connected to independent A-D converters 12. .13, and the microcomputer 150 via the input/output interface 14.
CPU K is input.

The microcomputer 15 includes a ROM for storing programs, a RAM, and a clock generator in CPU #1. The contents of the program are shown in FIG. 8 and will be described later. Key signals on the operation panel 1 are also input to the microcomputer 15 via the interface 14. The magnetron 9 is driven via a commercial AC power supply 16, a contact 18 of a microwave drive relay 17, a door switch 19, a step-up transformer 20, and the like. The microwave drive relay 17 is controlled by the CPU via the interface 14 and the transistor 21.

In the embodiment, the microcomputer is a clean computer MZ-8Qc, and the interface is MZ-80110. : Universal fk l/O car)”MZ 801/0
1. PIO-2025 (manufactured by I-0 Data Equipment Co., Ltd.) was used as an A-D converter.

FIG. 5 shows how the terminal voltage VG of the gas sensor 7 changes over time depending on the type of food being cooked. Depending on the ingredients contained in the food, for example, ethyl alcohol 78,360, acetic acid 118°0, acetaldehyde 20.8'O, etc., the boiling point differs, so it exhibits unique characteristics depending on the type of food.

On the other hand, if we assume that the terminal voltage VT of the thermistor 8 is used as the terminal voltage VGO of the gas sensor 7, as shown in FIG. They have almost the same characteristics and it is not possible to distinguish between the types of food.

Similar to thermistors, devices using infrared sensors and humidity sensors cannot distinguish the type of food.

Next, the operation of the embodiment of the present invention will be explained in more detail with reference to the characteristic diagram in FIG. 7 and the program flow chart in FIG. 8.

When you press the "Automatic heating" key 2 and then the heating key 6, the CPUdf receives the input signal, the microwave drive relay 17 is excited by the CPU command, the magnetron 9 oscillates, and the heating i! It begins. When time T elapses from the start of heating, the terminal voltage Vr of the gas sensor at that time
, is stored in RAM. Next, when time T has elapsed since the start, the gas sensor terminal voltage - is memorized again. The type of food is determined based on the size and the optimal finishing level is determined. For example, T1=30 seconds, T2=402~
For packaging with a 4-ply film, it falls within a certain range of steam to LO (shown as Va,=Vut=Vu in FIG. 7). In this way, the value is 0.95 ~
In the case of 1.0, the detection level is VUS, and this value is set to finish the preparation well, and is 0.9 to 0.9.
In the case of 5, the detection level is set to VDS, and this value is set so that the rice and soybean food have a good finish.If it is 0.9 or less, the detection level is set to VSS, and this value is set to give a suitable finish to sake sake. is set to be Once this setting is made, a continuous check of the gas sensor voltage VG is performed,
When the detection level is reached, the microwave drive is stopped.

Note that the terminal voltage VT of the thermistor can be used for overheating prevention and the like.

According to the present invention, by simply pressing one "auto heating key", the computer selects a heating program according to the type of food and is controlled to achieve the optimal finish, making the operation easy for the user. was made into

[Brief explanation of the drawing]

FIG. 1 is an external front view of a conventional example. Fig. 2 is an external front view of an embodiment of the present invention, Fig. 3 is a vertical sectional view of Fig. 2, Fig. 4 is a circuit diagram of the embodiment of the invention, and Fig. 5 is a diagram for explaining the present invention in detail. 6 is a characteristic diagram for explaining the comparative example, FIG. 7 is a characteristic diagram for explaining the operation of the embodiment of the present invention, and FIG. 8 is a characteristic diagram for explaining the operation of the embodiment of the present invention. 3 is a flowchart showing the contents of the program being executed. 1... Operation panel 2... Automatic heating key 7... Gas sensor 9... Macnetron 11... DC power supply 12... ... A-D converter 14 ... Interface 15 ... Microcomputer patent applicant Sharp Corporation agent Patent attorney Nishi 1) New-424- 'Zheng

Claims (1)

[Claims] A switching means for controlling the drive power of the microwave generator, a gas sensor provided in the exhaust passage of the heating chamber, a heating instruction switch commonly used for different types of food, and an input signal from the gas sensor. It also has a microcomputer that issues a heating stop command to the drive power source of the microwave generator according to a built-in program, and determines the type of food in the heating chamber based on the temporal rate of change of the input signal of the gas sensor. A microwave oven configured to set a level of a gas sensor that should issue the heating stop command according to the type of microwave oven.