JP2588294B2 - microwave - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a microwave oven that heats and cooks food with high frequency, and in particular, automatically identifies the type of food and sets conditions corresponding to the type. For a microwave oven that controls heating under pressure.

(Prior Art) A device that drives a magnetron and radiates radio waves to a heating chamber to heat food placed in the heating chamber is widely known as a microwave oven.

The heating time by the microwave oven varies depending on the type and amount of food when the radio wave output from the magnetron is constant, so in principle, the user determines the type and amount of food and sets a timer that is suitable for that. It is obtained by setting to. On the other hand, there are two types of conventional microwave ovens in which the heating time can be automatically stopped. The first method includes weight detection means for detecting the weight of food, and the heating time is predetermined for each type of food and its weight, and when the user inputs the type of food, the weight detection means is thereafter provided. The heating time is automatically determined based on the weight data provided by the company. The second method has gas detection means for detecting gas such as water vapor generated by heating, and monitors the gas generation state after the start of heating by this gas detection means. For example, the gas amount reaches a peak value. The heating time is automatically determined from the value obtained by multiplying the time required to reach by the coefficient determined by the type of food.In this case, it is necessary for the user to select the type of food. is there.

By the way, recently, convenience stores and the like sell several types of cooked foods that can be eaten only by heating,
The purchaser is also provided with a service that is warmed up by a microwave oven at the store, and the demand for a quick cooking operation is increasing.

(Problems to be solved by the invention) In order to automatically determine the heating time in the microwave oven,
In other words, in the conventional apparatus having a weight detecting means or a gas detecting means for automatically stopping the heating operation, in any case, the type of food must be manually selected by the user. However, the preparation operation for heating and cooking is troublesome, and for example, it is difficult to satisfy a demand for a quick operation for heating and cooking at the time of delivery at a convenience store or the like.

Therefore, an object of the present invention is to provide a microwave oven that can automatically identify the type of food within a certain range, and as a result, can minimize the number of manual operations at the start of heating cooking and improve the speed of operation. It is in.

[Structure of the Invention] (Means for Solving the Problems) A microwave oven according to the present invention has a size detecting means and a gas detecting means for respectively detecting the size of a container accommodating a food to be heated and a generated gas; Food type identification means for identifying the type of food from a combination of the size detection signal from the length detection means and the detection signal from the gas detection means, and a predetermined heating for each food identified by the food type identification means And control means for controlling the heating and cooking of the food under the conditions.

(Action) For example, in the case of cooked food sold at convenience stores or the like, the shape and size of the container are generally substantially determined for each type of food. In such a case, in the present invention, the provision of the food size detecting means makes it possible to use the size data detected by the size detecting means as one element for determining the type of food, and The combination of the size detection signal and the detection signal from the gas detection means makes it possible to automatically identify the type of food within a certain range, and the food is automatically identified under predetermined heating conditions based on the identification. The heating is controlled.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 3 showing a microwave oven main body, reference numeral 1 denotes a heating chamber formed in an outer box 2, in which a turntable 4 rotated by a motor 3 is disposed. A food (enclosed in a container) 5 which is heated by a radio wave radiated from a magnetron (not shown) provided in the inside into the heating chamber 1 is placed thereon. Door 6 that opens and closes the heating chamber 1 on the front
An operation panel 7 on which various operation members for heating control and a display are arranged is provided. As shown in FIG. 4, an infrared sensor 8 is provided above the heating chamber 1 of the microwave oven as a size detecting means for detecting a projected size of a food placed on the turntable 4 as a heating target. Have been. The infrared sensor 8 scans the inner bottom surface of the heating chamber 1, particularly on the turntable 4, based on a start command, and reads the temperature distribution. When the food is placed on the turntable 4, it is rare that the temperature between them is the same, and it is normal that there is a temperature difference, and the magnitude of the detection signal from the infrared sensor 8 is the temperature. Therefore, the size of the container containing the food can be determined by performing signal processing such as integration of the detection signal, for example.

The microwave oven has a gas sensor 9 for detecting water vapor and the like generated from food, and a weight sensor 10 for detecting the weight of the food placed on the turntable 4 (not shown in FIG. 3). And a temperature sensor 11 (not shown in FIG. 3) for detecting the temperature of the food, and a control circuit 13 constituted by a microcomputer for controlling the magnetron drive circuit 12.
Is provided. The control circuit 13 includes the above-described sensors 8 to
An input unit 14a that floats a detection signal from 11 as data, an operation unit 15 that calculates data input to the input unit 14a,
A storage unit 16 for storing various data, an output unit 14b, and a control unit 17 for controlling input, calculation, storage, and output operations
Consists of

In this embodiment, the types of foods to be automatically identified consist of five types classified into five categories, A, B1, B2, C1, and C2, as shown in Table 1, and the heating mode for these is thawing. The standard output (magnetron output) specific to each food is given. Among these foods, the rise in temperature after the start of heating is 5th for foods with high moisture belonging to categories B1 and B2.
In the figure, the curve shows a gradual change as shown by a curve 18, and the food belonging to the low moisture categories C1 and C2 shows a relatively steep change as shown by the curve 19. As for the rate of change in water vapor, food having a high moisture content belonging to categories B1 and B2 has a gradual change as shown by curve 20 in FIG. 6, whereas food having a low moisture content belongs to categories C1 and C2. The change is steep as shown at 21.

On the other hand, the standard output is 100 W for frozen foods belonging to category A, and 600 W for other categories.
Stipulated in

Next, the food type discriminating action and the heating cooking action of this embodiment will be described with reference to FIGS. 1 and 2. When the food is placed on the turntable 4 as it is stored in the container and a start switch (not shown) is turned on, the next operation is started.

That is, in the first step S1, the temperature detection signal from the temperature sensor 11 is read, and it is determined whether or not the temperature is 0 ° C. or less. If this is a frozen food, the determination is YES, the thawing operation is performed, and the end of thawing is monitored. (Steps S2, S3, S4). The end of the thawing is determined from the temperature detection signal of the temperature sensor 11 (step S5). If “thawing only” is set in advance for the heating cooking, the answer is YES and the operation ends here. If it is heating cooking, the determination becomes NO and the process moves to step S6, where the heating operation is started.

If the food on the turntable 4 does not require the thawing process, the temperature detection signal from the temperature sensor 11 exceeds 0 ° C., so the determination result in step S2 is NO, and the process proceeds to step S6. The heating operation is started. After the start of the heating operation, the control circuit 13 which has received the temperature detection signal from the temperature sensor 11 monitors the rising gradient of the temperature shown in FIG. 5, and determines whether or not the rising gradient is equal to or less than a predetermined set value α1.
That is, it is determined whether it is near the curve 18 or 19 in FIG. 5, and it is determined which of the categories B (B1, B2) and C (C1, C2). For foods with a lot of water, step S7
Is YES, and it is determined that it belongs to category B.

In step S8, the control circuit 13 receives the detection signal from the infrared sensor 8, determines the size of the container containing the food on the turntable 4, and determines whether the food is milk or stew. . When the shape or size is determined to be small, the category B1 corresponding to milk is selected, and when determined to be large, the category B2 to which the stew belongs is selected (steps S9, S10, S11). In contrast, step S7
When it is determined that the temperature gradient exceeds α1,
The food is identified as a food with low moisture belonging to the categories C1 and C2. Subsequently, in step S13, it is determined which of the categories C1 and C2 the food belongs to by the size detection signal from the infrared sensor 8. In this embodiment, it is assumed that a meat ham that is a category C1 food is stored in a relatively large rectangular container with a side food such as vegetables in a relatively large rectangular container and sprinkled with a source that easily absorbs radio waves on the surface. When the size is determined to be large, category C1 is selected as meaning hamburger, and when determined to be small, category C2 to which meat b belongs is selected (S14, S15).

After the control circuit 13 selects one of the five categories, the weight sensor
Receiving the detection signal from 10, the weight of the food is determined, the output of the magnetron is switched from the standard output to a value corresponding to the actual weight, and the heating time is obtained by receiving the detection signal from the gas sensor 9 as shown in the curve of FIG. As illustrated in FIG. 21, an arithmetic operation for summing the time T0 to the inflection point and β1 × T0 is performed, and the cooking is ended when the time elapses. Here, β1 is a constant determined in advance according to the type of food.

Accordingly, in this microwave oven, heating cooking is automatically started and automatically terminated only by placing one of the five types of foods shown in Table 1 on the turntable 4 in the heating chamber 1 and pressing the start button. You.

It should be noted that the present invention is, of course, not limited to only the above examples, particularly the type of food is only an example,
Further, the infrared sensor may be used not only as the size detecting means but also as the temperature detecting means, and an image sensor may be used instead of the infrared sensor. Further, in the above embodiment, the type of food is determined from both the size detection signal and the temperature detection signal, but the detection signal combined with the size detection signal is not limited to this, as illustrated in FIG. Since the generated gas differs depending on the food, it may be determined from a combination of the size detection signal and the gas detection signal, and the size detection signal may be a signal based on the characteristic of the shape, for example, a container containing the food. The signal may be based on height or width, and the automatic decompression function may be provided as needed.

[Effects of the Invention] According to the present invention, size detection means for detecting the size of a container containing food placed in a heating chamber is provided and the detection signal is used as one element of food type identification. Foods stored in containers that are somewhat standardized such as those sold for example are automatically identified and heating cooking is automatically performed, so the number of manual operations at the start of heating cooking is small In addition, it is possible to provide a microwave oven that can improve the speed of operation, such as promptly performing a heating and cooking service at a store delivery.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are flow charts for explaining an embodiment of the present invention, FIG. 3 is a partially cutaway front view of a microwave oven in the same embodiment, and FIG. FIG. 5 is a block diagram showing the electrical configuration of the embodiment, FIG.
FIG. 6 is a diagram showing steam generation characteristics of food. In the figure, 1 is a heating chamber, 3 is a motor, 4 is a turntable,
8 is an infrared sensor 8 (size detecting means), 9 is a gas sensor (gas detecting means), 10 is a weight sensor, 11 is a temperature sensor (temperature detecting means), and 13 is a control circuit (control means).

Claims (2)

(57) [Claims] 1. A size detecting means and a gas detecting means for respectively detecting a size of a container containing a food to be heated and a gas generated from the food to be heated, a size detection signal from the size detecting means and a gas detection. Food type identification means for identifying the type of food from a combination with a detection signal from the means, and control for controlling heating and cooking of the food under predetermined heating conditions for each food identified by the food type identification means A microwave oven comprising means. 2. The control means sets a high-frequency output according to a temperature detection signal from the temperature detection means prior to the heating operation. The microwave oven according to claim 1, wherein the microwave oven is stopped.