JPH06193882A - Cooker - Google Patents

Abstract

PURPOSE:To permit automatic cooking without any uneveness in the finishing of cooking by a method wherein the surface temperature itself of a food is measured correctly without being affected by the kind, configuration, number of pieces, conditions of arrangement and the like of the food. CONSTITUTION:A correcting means 8b estimates a ratio S of an area, occupied by a food in the temperature measuring area of a food temperature detecting means 5, based on the outputs of a weight of food detecting means 9 and a menu selecting means 7 while a food temperature information, outputted from the food temperature detecting means 5, is corrected in accordance with the ratio S of the area. According to this method, the temperature of the food itself can be measured correctly without being affected by the kind, configuration, number of pieces, conditions of arrangement and the like. On the other hand, a control means 6 controls a cooking means 4 based on the output of the correcting means 8b whereby automatic cooking, without any variability in the finish of cooking, can be effected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooking device for measuring food temperature for the purpose of automatic cooking.

[0002]

2. Description of the Related Art In a conventional automatic cooker, the surface temperature of a food item is detected and the rate of temperature rise is detected accordingly.
Japanese Unexamined Patent Publication No. 59-2013 discloses an automatic cooker which automatically estimates the size of a food item from the temperature rise rate and automatically cooks it.
No. 87 publication.

4 and 5 are views of the above-mentioned conventional publications. In FIG. 4, a cooked food 42 is placed in the heating chamber 41 of the microwave oven.
Is equipped with a magnetron (not shown) for generating high-frequency energy, which heats the food. Reference numeral 44 denotes an infrared sensor that detects infrared rays emitted from the surface of the cooked food 42.

Since the food shown in FIG. 4 (a) is large in size, high frequencies are absorbed near the surface of the food and do not reach the center. Therefore, the surface is heated, but the central portion is hard to be heated, and a temperature difference can be created in the food.

Since the food shown in FIG. 4 (b) is small in size, the high frequency is absorbed almost entirely and the temperature difference is small.

FIG. 5 shows that when heated at the same high frequency output,
It shows the difference in temperature rise depending on the size of the food,
The horizontal axis shows the heating time T, and the vertical axis shows the surface temperature tsr of the food. That is, it is shown that the temperature rise width when heating Tch for a predetermined time from the start of heating differs depending on the size of the food, and the size of the food F ₃ is small and changes from F ₂ to F ₁ as the size of the food increases. I will do it. When the cooked food is large, only D ₁ rises with respect to the heating of Tch, and as the cooked food becomes smaller, the rising rate increases from D ₂ to D ₃ . Utilizing the fact that the temperature increase rate depends on the size of the cooked product, the size of the cooked product is estimated by detecting the temperature increase rate. Therefore, there is an automatic cooker that changes the completion determination temperature depending on the size of the food to eliminate the difference in the finished product.

[0007]

However, in the above-mentioned conventional configuration, the food temperature detecting means is the average surface of the food or the container containing the food placed near the center of the cooking table in the field of view of the infrared sensor. Since only the temperature can be measured, the temperature of the food cannot be accurately detected when the shape of the food is small with respect to the temperature measurement region (field of view range) of the infrared sensor or when the food is placed near the end of the cooking table. Therefore, there is a problem that the automatic cooking is incomplete and the cooking results vary.

The present invention solves the above-mentioned problems, and by accurately measuring the surface temperature of the food itself without being influenced by the type, shape, number, and placement of the food, there is no variation in the finished product. It is intended to provide a cooking utensil capable of automatic cooking.

[0009]

In order to achieve the above object, the cooking utensil of the present invention according to claim 1 is a cooking means for cooking food placed in a cooking chamber, and a menu for selecting a food cooking menu. Selection means, and food temperature detection means composed of an infrared sensor for detecting the temperature of food in a non-contact manner,
Estimating the emissivity of the food or container based on the output from the menu selecting means, and correcting means for correcting the food temperature information output from the food temperature detecting means according to this emissivity, and based on the output from this correcting means And a control means for controlling the cooking means.

The cooking utensil of the present invention according to claim 2 is a cooking means for cooking food placed in a cooking chamber, a menu selecting means for selecting a food cooking menu, and a weight detecting means for detecting the weight of the food. An area occupied by the food in the temperature measuring area of the food temperature detecting means based on the output from the food temperature detecting means composed of an infrared sensor for detecting the temperature of the food without contact and the weight detecting means or the menu selecting means. A ratio is estimated, and a correction means for correcting the food temperature information output from the food temperature detection means according to the area ratio, and a control means for controlling the cooking means based on the output from the correction means are provided. is there.

[0011]

According to the present invention, since the correction means switches the emissivity of the object whose temperature is to be measured according to the menu, the temperature can be measured with higher accuracy. Because the voltage V (V) output from the infrared sensor is generally proportional to the incident energy, T ₁ (K): object temperature T ₀ (K): infrared sensor atmosphere temperature η: object emissivity K: constant Then, based on the Stefan-Boltzmann law, V = K * (η * T ₁ ⁴ −T ₀ ⁴ ) ... (1) On the other hand, the emissivity η of the object has a different value depending on the type of food and container. (For example, water is about 0.94, ice is about 0.97, glass and pottery is about 0.92.
Etc. ) Therefore, when calculating the object temperature T ₁ , the emissivity η is not always converted into a constant value (1.0), but
The correction means estimates the emissivity η of the food and the container whose temperature is to be measured according to the cooking menu, so that the measurement error of the food temperature is reduced.

Further, the correction means estimates the area ratio occupied by the food in the temperature measurement area of the food temperature detection means based on the output from the weight detection means or the menu selection means, and the food temperature detection means determines the area ratio according to the area ratio. By correcting the output food temperature information, the temperature of the food itself can be estimated even if the food is present only in a part of the temperature measurement area of the temperature detecting means.

(1) When food is heated and cooked by the cooking means, the temperature rise gradient of the food itself and the temperature rise gradient of the food other than the food such as the cooking table are significantly different. (2)
In general, when food does not completely occupy the temperature measurement area of the food temperature detecting means, the temperature of the food and the other temperature are averaged and detected corresponding to the area ratio occupied by the food. Therefore, by estimating the quantity and shape of the food based on the outputs from the weight detecting means and the menu selecting means, the measurement error of the food temperature is reduced.

[0014]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to FIG. There is a cooking table 3 for placing the food 2 in the cooking chamber 1, the cooking means 4 for cooking the food 2, the food temperature detecting means 5 for detecting the temperature of the food 2 in a non-contact manner, and the food temperature detecting means 5. The control means 6 controls the cooking means 4 based on the output. Further, the control means 6 is connected to a menu selection means 7 including operation keys for instructing automatic cooking after selecting one menu from a large number of cooking menus.

The cooking table 3 is a turntable which constantly rotates the food 2 (for example, makes one revolution in 10 seconds) when the food 2 is heated by radio waves by the cooking means 4 in order to reduce uneven heating of the food 2.

The cooking means 4 comprises an oven or a magnetron and heats and cooks the food 2 in accordance with the control amount given by the control means 6.

The food temperature detecting means 5 has a wide field of view.
The thermopile type infrared sensor of the element is fixed to the ceiling surface of the cooking chamber 1, and the thermal energy radiated from the food 2 placed near the center of the cooking table 3 through the opening window is detected in a non-contact manner to detect the temperature. Convert to. When the temperature measuring area of the infrared sensor is circular, the temperature measuring area corresponds widely around the center point of the cooking table 3. Now, V (V): voltage output from the infrared sensor T ₁ (K): object temperature T ₀ (K): infrared sensor atmosphere temperature η: emissivity of the object, then η * T ₁ = a * V + b (2) Here, since a and b can be expressed as a function of T ₀ , if the atmospheric temperature T ₀ (K) of the infrared sensor is known, η : Emissivity of object and object temperature T ₁ (K)
The product of can be uniquely determined. That is, the food temperature detecting means 5
Measures the voltage V (V) output from the infrared sensor and the ambient temperature T ₀ (K) of the infrared sensor, and calculates η * T ₁ (K)
To the correction means 8a.

The correcting means 8a is connected to a menu selecting means 7 including operation keys for instructing automatic cooking after selecting one menu from a large number of cooking menus. For example, when this menu is "thaw" of frozen food, the correction means 8a sets the emissivity η of the object to be η = 0.97, and in the case of "milk warming", assuming a standard mug and milk η
= 0.93, assuming a sake bottle with a tall sake η =
It is set to 0.92. In this way, the emissivity η of the object (food or container) whose temperature is to be measured is estimated for each menu. Next, the value of η * T ₁ (K) transmitted from the food temperature detecting means 5 is divided by this estimated emissivity η to calculate the temperature T ₁ (K) of the food itself and inform the control means 6. . Here, the emissivity η is assumed to be a constant value if the menu is decided, but it is made variable according to the food temperature, for example, taking into consideration that the emissivity η decreases in the process of changing the ice into water. Good. Further, the menu selection means 7 may be automatically selected instead of being selected by the user with the operation keys.

In the above construction, the correction means 8a estimates the emissivity η of the food and the container to be temperature-measured according to the cooking menu, so that the measurement error of the food temperature is reduced.

(Embodiment 2) Next, Embodiment 2 of the present invention will be described with reference to FIG.
Will be explained. The food temperature detecting means 5 has a wide field of view.
It consists of a single-element thermopile type infrared sensor,
It is fixed to the ceiling surface of the cooking chamber 1 and has a cooking table 3 through an opening window.
Energy radiated from food 2 placed near the center of
Is detected without contact and converted to temperature. Infrared sensor measurement
If the temperature area is circular, the temperature measuring area completely covers the cooking table 3.
Widely provided to cover. Now, V (V): voltage T output from the infrared sensor₁(K): Object temperature T₀(K): Assuming the infrared sensor ambient temperature, T₁= A * V + b (3) where a and b are T₀Atmospheric temperature T of the infrared sensor₀(K) is
If you know, the target temperature T ₁(K) can be uniquely determined
It That is, the food temperature detecting means 5 outputs from the infrared sensor.
Voltage V (V) and infrared sensor ambient temperature T
₀(K) is measured and T₁Correcting means 8b by converting to (K)
Tell.

Reference numeral 9 is a weight detecting means for detecting the weight of the food 2 placed on the cooking table 3, and is a menu selecting means consisting of operation keys for instructing automatic cooking after selecting one menu from a large number of cooking menus. 7 and the correction means 8b. The correction means 8b estimates the area ratio occupied by the food 2 in the temperature measurement area of the food temperature detection means 5 based on the outputs from the weight detection means 9 and the menu selection means 7. An example of this area ratio estimation method will be described. When the cooking menu and the weight of the food 2 are decided, the shape of the food 2 itself or the shape of the container to be put in is almost decided as shown in FIG. 3 due to the nature of the food. If the food is known, the weight of the food 2 can be easily back-calculated by detecting the weight of the food 2 by the weight detecting means 9. From these, the area ratio occupied by the food 2 in the temperature measuring region widely provided so as to completely cover the cooking table 3 can be estimated. Here, s: Occupied area ratio of food 2 (0 ≦ s ≦ 1) V (V): Voltage output from infrared sensor T _1o (K): Food temperature in temperature measurement region T _1p (K): Temperature measurement Temperature other than food in region T ₀ (K): Assuming infrared sensor ambient temperature, V = s * (T _1o −b) / a + (1−s) * (T _1p −b) / a ・ (4 ) Here, a and b can be expressed as a function of T ₀ . Further, it can be said that the temperature rise of the food other than the food is not so large as compared with the temperature rise of the food due to the heating and cooking. Therefore, _assuming that the temperature T _1p of the food other than the food in the temperature measurement region is derived from the infrared sensor atmosphere temperature T _0. , (4) expression _{V = s * (T 1o -b} ) / a + (1-s) * c ········· (5) where a, b, c is a function of T ₀ It can be transformed. When s = 1, the equations (4) and (5) are T ₁ (K) = T _1o (K) according to the equation (3). Normally, T _1p ≦ T ₁ ≦ according to the area ratio s. T _1o or T _{1o ≤T 1 ≤T 1p} . By correcting the food temperature information T ₁ output from the food temperature detecting means 5 to T _1o according to the area ratio s, even if the food exists only in a part of the temperature measuring area of the temperature detecting means, the food It can estimate its temperature. However, in reality, the sensitivity may be different between the central portion and the peripheral portion even in the temperature measuring area (the same area) due to the influence of the directional characteristics of the infrared sensor, etc. Therefore, it is more accurate to perform the correction by the position.

In the above structure, the correction means 8b estimates the area ratio s occupied by the food in the temperature measurement region of the food temperature detection means 5 based on the output from the weight detection means 9 or the menu selection means 7, and this area ratio s According to the food temperature detection means 5
By correcting the food temperature information output from the food 2, the temperature of the food 2 itself can be accurately estimated even if the food 2 exists only in a part of the temperature measurement region of the temperature detecting means 5, that is, the measurement of the food temperature. This has the effect of reducing the error. In addition, the food 2 can be measured anywhere on the cooking table 3, and the amount and shape of the food 2 can be handled.

[0023]

As described above, the present invention has the following effects.

(1) Estimating the emissivity of foods and containers to be measured according to the cooking menu reduces the measurement error of food temperature.

(2) When the shape of the food is small with respect to the temperature measurement area of the food temperature detecting means, when the food is scattered, or when the food is placed near the end of the cooking table, the temperature of the food is controlled. Can be accurately detected. It can also be applied to the quantity and shape of food.

Therefore, the surface temperature of the food itself can be measured more accurately without being influenced by the type, shape, number, and placement of the food, and automatic cooking with no variation in the finished product can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a cookware according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a cookware according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a shape of a temperature measurement target object corresponding to a menu and a weight in the embodiment.

FIG. 4 is a cross-sectional view of a main part showing a difference in a heating state due to a difference in size of a cooked material in a conventional cooking utensil.

FIG. 5 is a characteristic diagram showing a rise in the surface temperature of the cooked food according to the size of the cooked food in the conventional cookware.

[Explanation of symbols]

 4 cooking means 5 food temperature detecting means 6 control means 7 menu selecting means 8a correcting means 8b correcting means 9 weight detecting means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Nitta 1006 Kadoma, Kadoma City, Osaka Prefecture, Matsushita Electric Industrial Co., Ltd. (72) Hideki Terasawa, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A food temperature comprising cooking means for cooking food placed in a cooking chamber, menu selection means for selecting a cooking menu for the food, and infrared sensor for non-contact detection of the temperature of the food. A detecting means, a correcting means for estimating the emissivity of the food or the container based on the output from the menu selecting means, and correcting the food temperature information output from the food temperature detecting means according to the emissivity; and the correcting means. And a control means for controlling the cooking means based on an output from the cooking utensil. 2. Cooking means for cooking food placed in a cooking chamber, menu selection means for selecting a cooking menu for the food, weight detection means for detecting the weight of the food, Estimating the area ratio occupied by the food in the temperature measurement region of the food temperature detecting means based on the output from the food temperature detecting means composed of an infrared sensor for detecting the temperature and the weight detecting means or the menu selecting means. ,
A cooking utensil comprising: a correction unit that corrects the food temperature information output from the food temperature detection unit according to the area ratio; and a control unit that controls the cooking unit based on the output from the correction unit.