JPH06251866A - Microwave oven - Google Patents

Abstract

PURPOSE:To regularly heat a food with good efficiency by calculating the weight of the food by a sensor means and a calculating means, reading the best reflecting plate angle from a memory means by a control means, and setting the reflecting plate to this angle by a variable means. CONSTITUTION:The microwave reflected by a food in a heating chamber is detected by a sensor means 102, and the weight of the food is calculated according to the output by a calculating means 103. Since a memory means 104 preliminarily stores the food weight, the angle of a reflecting plate, and the relation of supplying efficiency of microwave to food, a control means 105 reads the angle of the reflecting plate capable of most efficiently supplying the microwave to the food of the calculated weight from the means 104 and controls a variable means 101 to set the reflecting plate to the read angle. Thus, the weight of a food to be heated is automatically measured, and the microwave supplying condition of the optimum impedance to the weight can be automatically regulated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a microwave oven for cooking food.

[0002]

2. Description of the Related Art In a conventional microwave oven of this type,
It is known that the user presets the weight of food to be cooked (object to be heated) and changes the supply state of the heating microwave to the food based on the setting information (for example, , JP-A-63-195994).

That is, in the conventional microwave oven, when the microwave output from the microwave source is supplied to the food in the heating chamber through, for example, a reflector, preset information (object to be heated) is used. The angle of the reflector is changed based on the weight of the microwave, and the output of the microwave source and the impedance of the load are matched so that the food is heated most efficiently.

[0004]

However, in such a conventional microwave oven, the user has to set the weight of the object to be heated in advance, so that there is a problem that it takes time to use the microwave oven. there were.

The present invention has been made in consideration of the above circumstances, and automatically measures the weight of food in the heating chamber and supplies microwaves so that the impedance becomes optimum with respect to the weight. A microwave oven capable of automatically adjusting conditions.

[0006]

According to the present invention, as shown in FIG. 1, microwaves output from a microwave source are supplied to a heating cabinet through a reflector so that foods placed in the heating cabinet can be cooked. In the microwave oven configured as described above, the variable means 101 that can support the reflector and change its angle, the sensor means 102 that detects the microwave reflected by the food in the heating chamber, and the sensor means 102. Calculating means 103 for calculating the weight of food in the heating chamber by receiving the output of
And a storage means 104 that stores in advance the relationship between the food weight, the angle of the reflector, and the microwave supply efficiency to the food, and the reflector that can most efficiently supply the microwave to the food of the calculated weight. The angle is read from the storage means 104, and the changing means 101 is set so that the reflector is set to the read angle.
The microwave oven is provided with a control means 105 for controlling the.

Further, according to the present invention, as shown in FIG. 2, the microwave output from the microwave source is supplied to the inside of the heating chamber through the antenna to heat and cook the food placed in the heating chamber. In the above microwave oven, the variable means 20 capable of supporting the antenna and changing the angle thereof.
1, sensor means 202 for detecting microwaves reflected by the food in the heating cabinet, calculation means 203 for calculating the weight of the food in the heating cabinet by the output of the sensor means, food weight, the angle of the antenna and the microwave. The storage means 204 in which the relationship of the supply efficiency of the waves to the food is stored in advance, and the angle of the antenna capable of supplying the microwave with the calculated weight of the food most efficiently is read from the storage means 204, and the read angle The microwave oven is provided with a control unit 205 that controls the variable unit 201 so that the antenna is set to the.

Further, according to the present invention, as shown in FIG.
It is possible to change the height of the turntable in a microwave oven configured to supply microwaves output from a microwave source to a heating cabinet and heat food to be placed on the turntable of the heating cabinet. Variable means 301
A sensor means 302 for detecting microwaves reflected by the food in the heating cabinet, a calculating means 303 for calculating the weight of the food in the heating cabinet by receiving the output of the sensor means 302, the weight of the food, the height of the turntable and the microwave. The storage means 304 in which the relation of the supply efficiency of the waves to the food is stored in advance, and the turntable height at which the microwave can be most efficiently supplied to the calculated weight of the food are read out from the storage means 304 and read out. The present invention provides a microwave oven including a control unit 305 that controls a variable unit 301 so that a turntable is set to a height. Incidentally, the above control means,
The calculation means and the storage means are a CPU, a ROM and an RA.
It is preferably constituted by a microcomputer provided with M.

[0009]

In FIG. 1, the sensor means 102 detects the microwave reflected by the food in the heating chamber, and the calculating means 10
3 receives the output of the sensor means 102 and calculates the weight of the food. Since the storage means 104 stores in advance the relationship between the food weight, the angle of the reflector and the microwave supply efficiency to the food, the control means 105 is most efficient for the food of the weight calculated by the calculating means 103. The angle of the reflector capable of supplying the microwave is read from the storage means 104,
The variable means 101 is controlled so that the reflector is set to the read angle.

In FIG. 2, the sensor means 202 detects the microwave reflected by the food in the heating chamber, and the calculating means 203 receives the output of the sensor means 202 to calculate the weight of the food. Since the storage means 204 stores in advance the relationship between the weight of food, the angle of the antenna, and the efficiency of microwave supply to food, the control means 205 uses the weight of the food calculated by the calculation means 203 in the most efficient microwave. The angle of the antenna that can supply the wave is read from the storage unit 204, and the variable unit 201 is controlled so that the antenna is set to the read angle.

In FIG. 3, the sensor means 302 detects the microwave reflected by the food in the heating chamber, and the calculating means 303 receives the output of the sensor means 302 to calculate the weight of the food. Since the storage means 304 stores in advance the relationship between the food weight, the height of the turntable, and the microwave supply efficiency to the food, the control means 305 causes the calculation means 303.
The height of the turntable that can most efficiently supply the microwave to the food of the weight calculated in step S3 is read from the storage means 304, and the variable means 301 is controlled so that the turntable is set to the read height. To do.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. This does not limit the present invention.

First Embodiment FIG. 4 is a structural explanatory view showing a first embodiment of a microwave oven according to the present invention, in which 1 is a control unit, 2 is a waveguide, 3 is a magnetron, 4 is a heating chamber, and 5 is A turntable, 6 is a motor for driving the turntable 5, 7 is food placed on the turntable 5, 8 is a microwave sensor, 9 is a slit provided on the wall surface of the heating chamber 4, and 10 is reflection of microwaves. A plate, 11 is a reflector driving device, and 12 is an opening provided in the ceiling of the heating cabinet 4.

FIG. 5 is a block diagram showing a circuit of the control unit 1 of the microwave oven shown in FIG. 4, where L is an amplifier circuit for amplifying the output of the microwave sensor 8, M is a CPU,
A control unit equipped with a microcomputer including a ROM, a RAM and an I / O port, and K is a keyboard equipped with keys for inputting cooking conditions, cooking start, test operation and the like.

The control unit M is adapted to drive the magnetron 3, the turntable motor 6 and the reflector driving device 11 in response to the outputs from the amplifier circuit L and the keyboard K.

As shown in FIG. 5, the microwave sensor 8 comprises a micro slit antenna 13, a diode 14, a condenser C, and resistors R1 to R3. Further, in the ROM of the control unit M, the angle data of the reflection plate 10 that most efficiently supplies the microwave to the weight of the food (object to be heated) is recorded in advance.

In such a structure, the magnetron 3
The microwave oscillated from propagates through the waveguide 2 and is applied to the food 7 in the heating chamber 4 through the opening 12. Part of the irradiated microwave is absorbed by the food 7 and the other part is consumed as heat by the inside wall of the refrigerator, etc., and another part is reflected by the slit 9 to the microwave sensor 8. And then go out.

The microwave sensor 8 receives the electric wave leaking from the slit 9 by the microstrip antenna 13 formed on the double-sided substrate, and the detection diode 14
It is output as a sensor signal to the control unit 1 via. The control unit 1 calculates the food weight from the sensor signal, reads the optimum angle of the reflector plate 10 to which microwaves are most efficiently supplied from the ROM, and reflects it so that the reflector plate 10 has the optimum angle. Plate drive device 1
Control 1

3 and 4 show the equal output curves illustrated on the Smith chart of the magnetron 2. Normally, when the reflection plate 10 is fixed, the operating point of the magnetron 3 becomes as shown in FIG. 3 according to the load (object to be heated). A1
Is a water load of 2 liters, B1 is a water load of 1 liter, C
1 is a water load of 0.5 liters, D1 is a water load of 0.3 liters, and E1 is each operating region at a water load of 0.1 liters. FIG. 3 shows that the energy supplied from the magnetron 3 to the load decreases from A1 to E1. In other words, the efficiency drops significantly as the load becomes lighter.

This state is shown in FIG. Figure 5
Is a graph showing Q = (energy absorbed by each load from magnetron 3) / (energy absorbed by 2 liters of water load from magnetron 3) × 100 when the output of magnetron 3 is constant and the load is changed. Yes, it shows that as the load decreases, the Q greatly decreases.

On the other hand, in this embodiment, the microwave sensor 8 detects the reflected microwaves, and as described above,
The control unit 1 adjusts the angle of the reflection plate 10 so that the microwave is most efficiently supplied to the weight of the object to be heated. This allows the magnetron 3 at light load
The operating point of moves as shown in FIG.

In FIG. 4, A2 is a water load of 2 liters, B2 is a water load of 1 liter, C2 is a water load of 0.5 liters, D2 is a water load of 0.3 liters, and E2 is a water load of 0.1 liters. ing. Therefore, in FIG. 5, the characteristic of Q with respect to the change of the load is as shown in (b), and it is understood that the energy is efficiently supplied from the magnetron 3 to the load even if the load, that is, the weight of the object to be heated changes. .

Second Embodiment FIGS. 9 and 10 are views corresponding to FIG. 4 and FIG. 5, respectively, showing a second embodiment of the present invention. In these figures, 20 is a feeding antenna that supplies the microwave output from the magnetron 3 to the inside of the heating chamber 4, 21 is a rotating device that supports and rotates the antenna 20, and the ROM of the control unit M stores it in advance. The data of the rotation angle of the power feeding antenna 20 in which the microwave is absorbed most efficiently with respect to the weight of food is recorded. The other construction is the same as that of the first embodiment.

In such a structure, the magnetron 3
The microwaves oscillated from propagate through the waveguide 2 and are applied to the food 7 in the heating cabinet 4 via the feeding antenna 20. A part of the irradiated microwave is absorbed by the food 7, another part is consumed as heat by the inner wall of the heating chamber 4 and the like, and another part is radiated from the slit 9 to be microwaved. It is detected by the sensor 8.

The control unit 1 calculates the food weight from the output signal of the sensor 8 and reads from the ROM of the control unit M the optimum angle of the power feeding antenna 20 in which the microwave is absorbed most efficiently for the food of that weight. The rotation device 21 is driven so that the feeding antenna 20 has the optimum angle. As a result, even if the weight of food (load) changes,
As shown in FIGS. 7 and 8B, the load can efficiently absorb the microwave energy.

Third Embodiment FIGS. 11 and 12 are views corresponding to FIG. 4 and FIG. 5, respectively, showing a third embodiment of the present invention. In these drawings, reference numeral 30 denotes a rotary lifting device that supports the turntable 5 to rotate and lift it.
In M, the height data of the turntable 5 at which microwaves are most efficiently absorbed with respect to the weight of food is recorded in advance. The other construction is the same as that of the first embodiment.

In such a structure, the magnetron 3
The microwave wave oscillated from the microwave propagates through the waveguide 2 and is applied to the food 7 in the heating chamber 4 through the opening 12. Part of the irradiated microwave is absorbed by the food 7,
The other part is consumed as heat by the inner wall of the heating cabinet 4,
Still another part is emitted from the slit 9 and detected by the microwave sensor 8.

The control unit 1 calculates the food weight from the output signal of the sensor 8 and determines from the ROM of the control unit M the optimum height of the turntable 5 that most efficiently absorbs microwaves for the food of that weight. Rotating and lifting device 3 so that the height of the turntable 5 is read out and becomes the optimum height.
Control 0. As a result, even if the weight of the food (load) changes, the load can efficiently absorb the microwave energy as shown in FIGS. 7 and 8B.

[0029]

According to the present invention, even if the object to be heated (load) changes, the microwave propagation condition is automatically set to the optimum condition in response to the change, so that the object to be heated is always efficiently maintained. Can be heated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a first invention.

FIG. 2 is a block diagram showing a basic configuration of a second invention.

FIG. 3 is a block diagram showing a basic configuration of a third invention.

FIG. 4 is an explanatory diagram of the configuration of the first embodiment.

FIG. 5 is a block diagram of a control circuit of the first embodiment.

FIG. 6 is a Smith chart showing the output characteristics of the magnetron of the comparative example.

FIG. 7 is a Smith chart showing the output characteristics of the magnetron of the example.

FIG. 8 is a graph showing the microwave supply characteristics with respect to the load of the example and the comparative example.

FIG. 9 is a view of the second embodiment corresponding to FIG. 4;

FIG. 10 is a view corresponding to FIG. 5 of the second embodiment.

FIG. 11 is a view corresponding to FIG. 4 of the third embodiment.

FIG. 12 is a view corresponding to FIG. 5 of the third embodiment.

[Explanation of symbols]

 1 Control Part 2 Waveguide 3 Magnetron 4 Heating Cabinet 5 Turntable 6 Motor 7 Food 8 Microwave Sensor 9 Slit 10 Reflector 11 Reflector Driver 12 Opening

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H05B 6/78 D 9032-3K

Claims (3)

[Claims] 1. A microwave oven configured to supply microwaves output from a microwave source to a heating cabinet through a reflecting plate to heat and cook food placed in the heating cabinet by supporting the reflecting plate. Variable means capable of changing the angle, a sensor means for detecting the microwave reflected by the food in the heating cabinet, a calculating means for receiving the output of the sensor means to calculate the weight of the food in the heating cabinet, A storage means that stores in advance the relationship between the weight of the food, the angle of the reflector, and the efficiency of microwave supply to the food, and the angle of the reflector that can most efficiently supply the microwave to the calculated weight of the food. A microwave oven equipped with control means for controlling the variable means so that the reflector is set to the angle read from the means. 2. A microwave oven configured to supply microwaves output from a microwave generation source to the inside of a heating cabinet through an antenna to heat and cook food placed in the heating cabinet, and to support the antenna. Variable means capable of changing the angle, sensor means for detecting microwaves reflected by food in the heating cabinet, calculation means for calculating the weight of food in the heating cabinet by receiving the output of the sensor means, and food A storage unit that stores in advance the relationship between the weight, the angle of the antenna, and the microwave supply efficiency to the food, and the antenna angle that can most efficiently supply the microwave to the calculated weight of the food is read from the storage unit. , A microwave oven provided with a control means for controlling the variable means so that the antenna is set to the read angle. 3. A microwave oven configured to supply microwaves output from a microwave generation source to a heating cabinet and heat food to be placed on the turntable of the heating cabinet, and change the height of the turntable. Variable means capable of controlling, a sensor means for detecting microwaves reflected by the food in the heating cabinet, a calculating means for calculating the weight of the food in the heating cabinet by the output of the sensor means, the food weight and the turn A storage unit that stores in advance the relationship between the table height and the supply efficiency of microwaves to the food, and the turntable height that enables the microwave to be supplied most efficiently to the food of the calculated weight are read from the storage unit, and A microwave oven equipped with control means for controlling the changing means so that the turntable is set to the read height.