JPH0587344A - Controlling device of heating for cooking appliance - Google Patents

Abstract

PURPOSE:To enable execution of uniform and highly precise heating by estimating a heating profile of foodstuff from a temperature difference between the center and the periphery and the speed of rise of temperature and by calculating a heating output corresponding to the foodstuff. CONSTITUTION:When foodstuff 2 is put in a heating chamber 3 and set on a saucer 9, the temperature of the foodstuff 2 is measured by an infrared ray 5 and it is judged whether a difference between the temperature of the foodstuff 2 and that of the heating chamber 3 before the foodstuff is put therein is a prescribed value or above. When the difference is judged to be the prescribed value or above, this foodstuff 2 is determined as the frozen one, indications of 'warning' and 'defreezing' are lighted and a driving control of a magnetron 4 corresponding to a key selected for either of these indications is conducted. When the difference is judged to be below the prescribed value, this foodstuff 2 is determined as not being the frozen one and a menu is selected by a user, a control therefor being conducted. When the user selects a menu of 'warning' a control of 'warning' is conducted in accordance with a temperature difference between the central part of the foodstuff 2 and the periphery thereof. According to this constitution, uniform and highly precise heating can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating control device for a cooker, and more particularly to a heating control function of a device for heating food such as a household microwave oven.

[0002]

2. Description of the Related Art Conventionally, a heating device has been proposed in which an infrared sensor is used to detect the surface temperature of food to control heating, but it is mainly used to detect the temperature of only the central position of food. Since there is a large difference in temperature between the central portion and the surroundings, since the average value is observed, inconveniences such as overheating and underheating are likely to occur.

[0003] For example, when reheating (warming) a hamburger or the like, the temperature rise in the central portion is slower than that in the peripheral portion, so there is a risk that the surroundings will burn when the temperature in the central portion is appropriate.

As described above, since foods have different half-depths (ease of passing radio waves) due to the influence of water content and salt content, it is almost impossible to uniformly heat any food at present. In the heating control based on the temperature detected in, the cooking function was limited.

Further, since the keys used for "warming" and "thawing warming" for reheating from a frozen state have the same cooking end temperature of 70 to 80 ° C., the humidity is measured using an absolute humidity sensor or the like. That is, the change in the amount of water vapor generated was detected and the same key was used for control.

However, since "thawed warmth" has a larger temperature change than "warmed warmth", there is a drawback that heating unevenness easily occurs in "thawed warmth" when heated with the same output.

[0007] In addition to "warmth" and "thawing warmth", "rapid live thawing" for rapidly thawing organisms is also necessary, which makes the distinction complicated, and as shown in Fig. 13, "warmth" and "thawing warmth" In addition to the above, "raw defrosting" is also required, so many keys are required and there is a problem in usability.

[0008]

As described above, the food is
It is almost impossible at present to uniformly heat any food because the half-depth differs due to the influence of water content and salt content. Therefore, in heating control based on the temperature detected at one point,
The cooking function was also limited.

Also, since the temperature rising rate differs depending on whether the heating is from the frozen state or the normal temperature state, it is necessary to perform different temperature control for each, and the operation becomes complicated when the key operation is performed. was there.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to improve cooking performance and simplify operation.

[0011]

Therefore, in the present invention, the surface temperature of the food is detected at a plurality of points from the center of the dish in the heating chamber to the surroundings, and the temperature difference between the center and the surroundings and the temperature rising rate are detected. Accordingly, the heating profile of the food is estimated, the heating output corresponding to the food is calculated, and the heating means is controlled.

[0012]

According to the above construction, the heating profile of the food is estimated according to the temperature difference between the center and the surroundings and the heating rate, and the heating output according to the food is calculated. It becomes possible to perform accurate heating.

Further, by measuring the temperature change when the food is put in the heating chamber, it is possible to detect whether or not the food is in a frozen state, for example. Heating can be performed.

Furthermore, the heating profile of the food can be estimated by measuring the temperature change in the initial stage of heating, and highly accurate heating control can be performed.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a diagram showing a microwave oven according to an embodiment of the present invention.

The microwave oven has a heating chamber 3 as a cooking chamber for heating food 2, a magnetron 4 for applying microwaves as heating energy to the food 2, and a ceiling portion of the body 1 in the microwave oven. An infrared sensor 5 composed of a thermopile installed so as to be movable, and a plurality of infrared passage ports 6 for transmitting infrared rays are arranged on the ceiling of this heating chamber. The infrared sensor 5 is conveyed to a position corresponding to these infrared passing ports 6, and the infrared rays from the food surface are transferred to the infrared passing ports 6.
The temperature is detected by the infrared sensor 5 via the, and the output of the magnetron 4 is adjusted thereafter to perform heating control based on the difference in surface temperature and the temperature change in each part of the food. 9 is a plate and 10 is a weight sensor for detecting the weight of food.

The output of the infrared sensor 5 is the signal processing circuit 11
It is input to the control unit 8 via the control unit 6 and controls the magnetron 4 and the drive of the drive unit 7.

Further, as shown in FIG. 2, the signal processing circuit 11 includes a temperature compensating section 12 for correcting the sensor signal by the temperature in the vicinity of the sensor, a filter 13 for filtering the output of the sensor 5, an amplifier 14, and a central portion. And RO that holds data such as the temperature difference or temperature rise rate at the edges
M, and a microcomputer 15 having an A / D converter for reading the sensor signal, and the like, and are also configured to perform processing by an output from a door opening / closing detection unit 16 which detects opening / closing of the door.

Further, as shown in FIG. 3, the control unit 8 controls the display of the display unit 19 according to the output of the signal processing circuit 11 shown in FIG. 2 and the instruction from the operation unit 20, and the heating control unit. The configuration includes a microcomputer 18 having a function of controlling the output of the magnetron via 17. Then, the temperature of the food is determined from the output of the door open / close detection unit 16 and the output of the sensor 5, the heating menu is displayed on the display unit, and when the user selects the menu, the output according to the menu is given by the command of the heating control unit 17. It is designed to control. That is, whether or not the food is frozen is automatically detected, and the user does not need to perform an input operation.

Therefore, as shown in FIG. 4, the display unit 16 has only two types, "warming" and "raw defrosting", and it suffices to specify either of them by key operation. Is easy. This is because the surface temperature of the food is measured, whereas in the conventional case, as shown in FIG. 13, the start key and “warm up”,
It was necessary to perform two key operations of selecting three types of menu keys, "raw defrosting" and "defrosting warming".

Next, the operation of this apparatus will be described with reference to the flowchart of FIG.

First, the temperature difference before and after the door 2 is opened and the food 2 is put in the heating chamber 3 is measured by the infrared sensor 5 to determine whether or not it is a frozen product, and the position of the food during heating. It is characterized in that the temperature difference is measured and the heating control is performed. Here, FIG. 6 shows the relationship between the food temperature and the control output for "warming", "fresh thawing", and "thawing warming". "Warm"
It is desirable to heat with full power in order to shorten the cooking time in order to raise the temperature from room temperature to 70 to 80 ° C, while “defrosting warm” is from -20 ° C to 70 to 80 ° C.
Although the temperature is raised to ℃, uneven heating easily occurs at full power, so once the thawing progresses, turn off the power,
Ensure uniform heating. Then, in order to reduce the cooking time, the power may be finally increased. In the case of "raw thawing", thawing is performed at a low output and the thawing is finished at around 0 ° C in order to obtain uniform thawing. Therefore, if the heating is controlled by detecting the temperature in the initial state, as shown in FIG. 4, "warming" and "thawing" can be performed with a single key operation. It can be seen that only one display is required.

These operations will be described step by step.

First, when the fact that the door has been opened can be notified to the microcomputer 15 by the output from the door opening / closing detection unit 16, a measurement instruction signal is issued to the infrared sensor, and the central portion of the plate 9 before the food is stored. The temperature (heating chamber temperature) is detected by the infrared sensor 5 (step 101). This detected temperature is T1.

When the food is stored in the heating chamber 3 and placed on the plate 9 (step 102), the infrared sensor 5 measures the temperature of the food 2 (step 103), and the food temperature T
It is determined whether or not the difference between 2 and the heating chamber temperature T1 before storage is a predetermined value a or more (step 104).

When it is judged that the food is a or more, it is assumed that the food 2 is a frozen product (step 105), and the "warming" and "raw thawing" indicators light up (step 10).
6) Then, control of magnetron drive according to any selected key is performed (steps 106 to 110).

If it is judged in the judgment step 104 that the food is smaller than "a", the food is not a frozen product, the user selects a menu and controls each of them (steps 111 to 114).

When the user selects the "warming" menu, the "warming" control is performed according to the temperature difference between the central portion and the peripheral portion of the food and the rising speed (step 1).
15-116).

In realizing this "warm" control,
First, the following experiment was conducted.

By using the microwave oven shown in FIG. 1 to detect the temperature change at each position a, b, c, d on the food surface as shown in FIG. The temperature rate and heating pattern were measured.

As a result, as shown in the temperature profile of each food item in FIG. 9, the group I such as rice and pilaf warms from the center, and potage soup, miso soup, curry, etc.
The II group warmed from the surroundings with a moderate temperature difference, and the III group such as hamburger and chikuzen boiled from the surroundings with a large temperature difference.

FIG. 10 shows the results of measuring the relationship between the central temperature of food and the heating time.

From these results, it was found that the heating patterns can be summarized for each group as shown in the table in FIG. Then, based on these results, the type of food is estimated from the change in surface temperature and heating control is performed accordingly.

This corresponds to steps 115 to 116 in the flowchart of FIG. Here, the temperature at each of the positions a to d is measured, and it is determined whether or not it belongs to any one of the groups I, II, and III depending on whether or not it is warm from the center and whether or not the temperature difference is large. Optimal control is performed according to each group. That is, in the case of the I and II groups, heating is performed at a constant output as shown in FIG. 12 (a), and in the case of the III group, the magnetron output is lowered midway because the temperature difference is large as shown in FIG. 12 (b). As a result, the temperature difference can be relaxed and local overheating can be prevented.

Next, the actual operation of this "warming" control will be described with reference to the flowchart shown in FIG.

First, the infrared sensor 5 is sequentially moved to each of the positions a to d shown in FIG. 8 to measure the surface temperature at each position (step 120), and then the magnetron 4 is turned on and the dish 9 is rotated. (Step 12
1).

After the lapse of a predetermined time, only the temperature at the central position a is measured, and when the predetermined temperature is reached, the magnetron 4 is once turned off, and the infrared sensor 5 is sequentially moved again to the respective positions a to d to move the infrared sensor 5 at each position. The surface temperature is measured (steps 122-124).

Then, it is judged whether or not the amount of change in temperature at the center position a at this time is A1 or more and the maximum value of the temperature difference at each position a to d in step 124 is B1 or less (step S1). 125), when the amount of change in temperature is A1 or more and the maximum value of the temperature difference at each of the positions a to d is B1 or less, it is determined that the food is in the group I and heating is continued for a predetermined time and finished. (Steps 126 to 127).

On the other hand, when the amount of change in temperature is smaller than A1, it is judged whether or not the maximum value of the temperature difference at each position a to d is not more than B1 (step 128), and at each position a to d. When the maximum value of the temperature difference is less than B1, it is determined that the food is a group II food, and heating is continued for a predetermined time and finished (steps 126 to 127).

Further, when the maximum value of the temperature difference at each of the positions a to d is larger than B1, it is determined that the food is a group III food, the magnetron output is turned down, and heating is continued for a predetermined time to end (step). 129-131).

As described above, according to the apparatus of this embodiment, heating is performed with a heating output according to the food, so that uniform heating can be performed efficiently.

Further, the keys for discriminating the food can be integrated, so that the keys can be simplified and the key operability can be improved.

In the above-described embodiment, one infrared sensor is moved to each position by the driving device to measure at each position, but a plurality of infrared sensors are used or each position is simultaneously measured by the infrared sensor array. The surface temperature may be measured at.

[0045]

As described above, according to the present invention, the heating profile of the food is estimated according to the temperature difference between the center and the surroundings and the heating rate, and the heating output according to the food is calculated. Therefore, uniform and highly accurate heating can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a microwave oven according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a signal processing circuit of the microwave oven.

FIG. 3 is a block diagram showing a control unit of the microwave oven.

FIG. 4 is a diagram showing a display unit of the microwave oven.

FIG. 5 is a diagram showing an operation flowchart of the microwave oven of the embodiment of the present invention.

FIG. 6 is a diagram showing a magnetron output characteristic in each menu of the microwave oven.

FIG. 7 is a view showing a flowchart of heating control steps of the microwave oven.

FIG. 8 is a diagram showing a relationship between a dish and a measurement position of the microwave oven.

FIG. 9 is a diagram showing the relationship between food, position, and temperature.

FIG. 10 is a diagram showing a relationship between food, heating time, and temperature.

FIG. 11 is a table showing the relationship between foods and ingredients and heating profiles.

FIG. 12 is a diagram showing a relationship between a heating output and a change in temperature difference according to each group.

FIG. 13 is a diagram showing a display unit of a conventional example.

[Explanation of symbols]

 1 Main Body 2 Food 3 Heating Room 4 Magnetron 5 Infrared Sensor 6 Window 7 Drive Section 8 Control Section 9 Dish 10 Weight Sensor 11 Signal Processing Circuit 12 Temperature Compensation Section 13 Filter 14 Amplifier 15 Microcomputer 16 Door Open / Closed Detection Section 17 Heating Control Section 18 Microcomputer 19 display unit 20 operation unit

Claims (1)

[Claims] 1. A heating chamber in which a dish on which food to be heated is placed is installed, heating means for heating the food, and surface temperatures of the food at a plurality of locations from the center to the periphery of the dish are detected. Temperature detection means, to estimate the heating profile of the food according to the temperature difference between the center and the surroundings detected by the temperature detection means and the temperature rising rate,
A heating control device for a cooking device, comprising: a control unit that calculates a heating output according to the food and controls the heating unit.