JP3316961B2 - Cooking equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to automatic cooking of food such as a microwave oven, and more particularly to a cooking apparatus provided with infrared detecting means for measuring the surface temperature of food in a non-contact manner.

[0002]

2. Description of the Related Art A conventional cooking apparatus of this type, for example, a microwave oven is described in Japanese Utility Model Laid-Open No. 58-158202. As shown in FIG. 5, there is a cooking table 4 for placing the food 2 and the dish 3 in the cooking chamber 1, a heating means 5 for cooking the food 2, and a food placed on the cooking table 4 in a non-contact manner. 2
Temperature detecting means 6 for detecting the temperature of the
When the output of the food 2 reaches a predetermined value, the food 2
And control means 7 for stopping the heating of the heater.

[0003] The cooking table 4 is a turntable that always rotates the food 2 (for example, makes one round in 10 seconds) when the food 2 is heated by radio waves by the heating means 5 in order to reduce uneven heating of the food 2.

[0004] The heating means 5 is made of a magnetron and heats the food 2 by microwave with a predetermined power output.

The temperature detecting means 6 is composed of, for example, a one-element thermopile type infrared sensor, is fixed to the ceiling surface of the cooking chamber 1, and radiates from the food 2 placed near the center of the cooking table 4 through an opening window. The detected heat energy is detected in a non-contact manner and converted into a temperature. FIG. 6 shows an example of the temperature detecting means 6. The temperature detecting means 6 is housed in a case 6a, and the thermopile 6
b, sensor window 6c and small hole 6d provided in case 6a
Are located concentrically. The thermosensitive viewing angle of the thermopile 6b is restricted to α by the sensor window 6c. The temperature-sensitive viewing angle α is increased to 70 ° to 120 ° in consideration of improvement in sensitivity. However, in a cooking device such as a microwave oven, the mounting position of the temperature detecting means 6 is the food 2 to be measured.
, The case 6a has a diameter of, for example, 1 cm.
A small hole 6d of about degree is provided, and the temperature-sensitive viewing angle is β (20 ° to 30 °).
゜). In the case of a microwave oven, making the opening a small hole 6d also has the meaning of preventing radio wave leakage.

As shown in FIG. 7, the distance L between the temperature detecting means 6 and the food 2 to be measured is 30 cm, and the temperature-sensitive viewing angle β
Is 20 °, the temperature-sensitive visual field is as follows: D = 2 * L * tan (β / 2) = 2 * 30 * tan10 ゜ (1) A large circle having a diameter D of about 10.6 cm (area indicated by oblique lines) ).

The thermopile 6b has a large number of thermocouple elements for receiving radiant heat (infrared rays) radiated from the food 2 and performing thermoelectric conversion. The thermocouple element takes out, as an electromotive force, a slight temperature difference generated between the hot junction and the cold junction due to the radiant heat radiated from the food 2, amplifies the temperature difference, and further converts and outputs the temperature of the food 2 by the cold junction temperature compensation. The configuration of the temperature conversion is widely known. (For example, “Transistor technology special edition, temperature / humidity sensor utilization handbook”;
Editor of Transistor Technology, CQ Publisher, 1988
Year. )

When a thermopile is used as the temperature detecting means 6, a chopper is not required as compared with a pyroelectric element or the like, so that it can be constructed inexpensively, but has the problem that the sensitivity is not large.

The structure of the thermopile 6b is described in, for example,
No. 196933. FIG. 8 is a plan view of the main part of the thermopile 6b as viewed from the back side (when infrared rays are incident from the front side). A square plate-shaped gold black 62 for absorbing infrared rays is arranged on the front side of the organic film 61. A thermocouple element 63 is provided at a position corresponding to the gold black 62 on the back side of the organic film 61. The thermocouple element 63 is made of a conductive material that connects the electrodes 64, and has four folded portions corresponding to each side of the gold black 62. That is, it is folded so as to alternately reciprocate between the inside and the outside along one side of the gold black 62, and two dissimilar metals (for example, bismuth and antimony) are alternately connected in series at each folded portion. Have been.
One of the joining portions 65 and 66 of the dissimilar metals is gold black 6
2, a hot junction 65 for detecting the amount of infrared rays, that is, gold black 62 whose temperature has been increased by infrared rays.
It has become. The other is a cold junction 66 located outside the gold black 62 and having a reference temperature. 6
7 is a thermistor for compensating the temperature of the cold junction 66. Therefore, the hot junction 65 and the cold junction 6 which are joining portions of dissimilar metals are formed.
A voltage value obtained by integrating the potential difference generated between the electrodes 6 and 6 is generated between the electrodes 64 at both ends, and the temperature of the hot junction 65 is detected from the voltage value. Thus, the problem that the sensitivity is not large is solved.

The output voltage from the thermopile 6b has a directional characteristic as shown in FIG. In FIG. 9, the horizontal axis is the temperature-sensitive viewing angle, which corresponds to the diagonal direction of the square of the gold black 62. The vertical axis represents the output voltage from the thermopile in percentage. Thus, the temperature-sensitive viewing angle β
It can be seen that the sensitivity varies greatly depending on the angle from the central axis 0 ° even inside the circle. The highest sensitivity is not on the center axis 0 ° but on the outer peripheral portion (around ± 5 ° in FIG. 9) corresponding to the position where the hot junctions 65 are arranged. This largely depends on the arrangement of the thermocouple elements 63. As can be seen from FIG. 8, since the hot junction 65 is far from the center point of the gold black 62, the sensitivity on the central axis 0 ° is considerably small (FIG. 9).
Is about 60% of the maximum sensitivity). In addition, the directivity does not have a concentric sensitivity distribution centered on the central axis 0 ° because the arrangement of the thermocouple elements 63 is square.

[0011]

However, in the above-mentioned conventional configuration, the temperature detecting means can measure only the average surface temperature of the food placed near the center of the cooking table in the temperature-sensitive field of view of the infrared sensor. If the shape of the food is small relative to the temperature field of view of the infrared sensor, or if the food is placed near the end of the worktop, dishes, containers, and worktops other than food will be in view and the food temperature will be accurately measured. Not detectable. Further, since the ratio of the food occupied by the rotation of the cooking table changes, the temperature of the food cannot be accurately detected.

Further, there has been another problem that the heating of the food by the heating means causes a part of the food to be scattered or steam to be generated, thereby contaminating the temperature detecting means, and consequently lowering the accuracy of the temperature detection.

On the other hand, there is a part of an industrial radiation thermometer to which a thermopile is applied, in which the arrangement of thermocouples is radially improved to improve the directivity, but the whole structure is complicated and expensive. There are various problems such as being heavy and difficult to drive when installed in a cooking apparatus, being unable to prevent leaking radio waves, and lacking heat resistance.

The present invention solves the above-mentioned problems, and accurately measures the temperature of the food itself without being affected by the type, shape, number, placement, etc. of the food.
It is an object of the present invention to provide a cooking apparatus capable of performing automatic cooking without variation in workmanship.

[0015]

In order to achieve the above object, a cooking apparatus according to the present invention comprises a heating means for heating food, a condenser lens for condensing radiant heat radiated from the food,
A thermopile in which a large number of radial thermocouple elements are arranged for thermoelectrically converting radiant heat from food collected by the condenser lens, and control means for controlling the heating means in accordance with an output of the thermopile; The contact is disposed at a position substantially coincident with the optical axis of the condenser lens.

[0016]

[0017]

Further, the control formula is as follows: heating control amount (W) = K ₁ (T−average temperature of food) −K
₂ (Temperature difference of food) T: Set temperature (° C.), K ₁ , K ₂ : Constant value, and control means controls heating means.

[0019]

According to the present invention, a temperature detecting means having a narrow temperature-sensitive visual field without deteriorating the sensitivity is formed because the condenser lens condenses the radiant heat radiated from the food. In particular, as a thermopile configuration, a large number of radial thermocouple elements are arranged, and the hot junction of the thermocouple element substantially coincides with the optical axis of the condenser lens, so that the sensitivity is concentrated around the optical axis of the condenser lens. That is, the output of the thermopile has a steep directional characteristic only at a specific portion of the food on the optical axis of the condenser lens.

[0020]

[0021]

[0022]

Further, by providing control means for controlling the heating means in accordance with the output of the temperature distribution measuring means and the difference from the set temperature, fine heating control according to the temperature unevenness of the food, the maximum temperature and the minimum temperature of the food, etc. (Adjustment of heating control amount, heating time, heating pattern, etc.) are realized.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same components as those in the conventional example are denoted by the same reference numerals.

As shown in FIG. 1, there is a cooking table 4 in which a food 2 and a dish 3 are placed in a cooking chamber 1.
Heating means 5 for cooking the food, temperature detecting means 8 for detecting the temperature of the food 2 placed on the cooking table 4 in a non-contact manner, and the temperature detecting means 8 is continuously reciprocated by 40 ° in the vicinity of the cooking chamber 1. Driving means 9 is provided. Further, a temperature distribution measuring means 10 for measuring a large number of temperature distributions of the food 2 based on a large number of outputs from the temperature detecting means 8 whose temperature-sensitive fields are sequentially switched by the driving means 9, and a temperature distribution measuring means 1
Control means 11 for controlling the heating means 5 according to 0 is provided, and further, there is provided a blocking means 12 for blocking radiant heat radiated from the food 2 to the temperature detecting means 8 when the food 2 is not heated by the heating means 5.

The cooking table 4 is a turntable that constantly rotates the food 2 when the heating means 5 heats the food 2 by radio waves in order to reduce uneven heating of the food 2, and makes one round in 10 seconds.

The heating means 5 is made of a magnetron and heats the food 2 by microwave with a predetermined power output.

The temperature detecting means 8 is composed of, for example, a one-element thermopile type infrared sensor, and radiates from the food 2 placed near the center of the cooking table 4 through an opening window provided on the ceiling surface of the cooking chamber 1. The detected heat energy is detected in a non-contact manner and converted into a temperature. The temperature detecting means 8 is shown, for example, as shown in FIG. The temperature detecting means 8 is a resin case 8 having a high heat insulating property.
a. Thermopile 8b is usually TO-5
Alternatively, it detects the radiant heat radiated from the object of temperature measurement through a sensor window 8d that is built in an aluminum can 8c called TO-18 and has high thermal conductivity and transmits infrared rays. Here, the cold junction temperature of the thermopile 8d is
c is thermally coupled.

Outside the sensor window 8d, a thin (about 0.3 mm thick) Fresnel lens 8e made of polyethylene that transmits infrared rays is provided. The Fresnel lens 8e is made of a material having a high thermal conductivity such as aluminum (for example, aluminum). ), And is thermally coupled to the can 8c. The lens holder 8f is painted black so as to prevent reflection of infrared rays (that is, to increase the emissivity), and is configured to always have a uniform temperature. The cold junction of thermopile 8d is
Can 8c, lens holder and Fresnel lens 8e
This has the effect of increasing the heat capacity and suppressing temperature fluctuations and, when the Fresnel lens 8e receives heat due to radiant heat from the temperature measurement target, quickly transmitting the temperature change to the cold junction temperature. Of course, by reducing the thickness of the Fresnel lens 8e, it is configured to be as hard to receive heat as possible.

Further, the lens holder is insulated by the resin case 8a and the air layer, and is configured so as not to be affected by the ambient temperature fluctuation outside the temperature detecting means 8. A stepped light-shielding screw is provided in the opening of the resin case 8a to prevent radiant heat from an object other than the temperature measurement object due to stray light from entering the Fresnel lens 8e. The inside of the resin case 8a is painted black to increase the emissivity, while the outside is white so that the emissivity is low. This is to make it difficult for the resin case 8a to be warmed by radiant heat radiated from the food 2 to be measured.

The temperature-sensitive viewing angle β is reduced to 3 ° by the Fresnel lens 8e. By providing small holes, the temperature-sensitive viewing angle β
In the conventional embodiment, the temperature detection means 8 having a very narrow temperature-sensitive field of view is formed, whereas the limit is about 20 ° at most. Now, assuming that the distance L between the temperature detecting means 8 and the food 2 to be measured is 30 cm and the temperature-sensitive viewing angle β is 3 °, the temperature-sensitive viewing field is D = 2 * L * tan (β / 2). = 2 * 30 * tan1.5 ゜ (2) A narrow circle (area indicated by oblique lines) with a diameter D of about 1.6 cm is obtained. This is about 0.15 times as large in diameter D as in the case where the temperature-sensitive viewing angle β is 20 °, and about 0.1 in the temperature-sensitive viewing area S.
The value is 022 times, which is an appropriate value as the spatial resolution for measuring the temperature of each part of the food 2.

FIG. 3 is a plan view of the main part of the thermopile 8b as viewed from the back side (when infrared rays are incident from the front side). A circular plate-shaped gold black 82 for absorbing infrared rays is arranged on the front side of the organic film 81, and a thermocouple element 83 is provided on the back side of the organic film 81 at a position corresponding to the gold black 82. The thermocouple element 83 is made of a conductive material that connects the electrodes 84, 84, and has 100 pairs of folded portions (only 15 pairs are shown in FIG. 3) so as to surround the center point of the gold black 82. I have. In each folded portion, two dissimilar metals (for example, bismuth and antimony) are radially connected in series so as to alternately reciprocate between the inside and the outside. One of the joining portions 85 and 86 of the dissimilar metals is located near the center point of the gold black 82 inside the gold black 82 and is connected to the gold black 82 whose temperature has been increased by infrared rays, that is, the hot junction 85 for detecting the amount of infrared rays. Has become.
The other is located outside the gold black 82 and serves as a cold junction 86 having a reference temperature. 87 is a cold junction 86
Is a thermistor that compensates for the temperature of Therefore, a voltage value obtained by integrating the potential difference between the hot junction 85 and the cold junction 86, which are the junctions of dissimilar metals, is generated between the electrodes 84, 84 at both ends, and the temperature of the hot junction 85 is detected from the voltage value. It has become. The diameter of the gold black 82 is determined based on the focal length f of the Fresnel lens 8e and the image height at which the temperature measurement target forms an image on the gold black 82 via the Fresnel lens 8e based on the viewing angle β (3 °). Have been. The heat capacity of the gold junction 82 and the hot junction 85 is set to be small, and the heat capacity of the cold junction 86 at the reference temperature is increased.
The organic film 81 is made of a heat-insulating material so that heat can be transferred to and from the cold junction 86 only by conduction heat transmitted through two dissimilar metals.

The output voltage from the thermopile 8b has a directional characteristic as shown in FIG. In FIG. 4, the horizontal axis is the temperature-sensitive viewing angle, and the vertical axis is the output voltage from the thermopile expressed as a percentage. The solid line shows the case where the Fresnel lens 8e was not provided.
The directional characteristics of the thermopile 8b itself, in which thermocouple elements are connected in series with 0 pairs, are shown, and the dotted lines indicate the overall directional characteristics when the temperature measurement field of view is narrowed by providing the Fresnel lens 8e. Since the hot junction 85 is close to the center point of the gold black 82, the sensitivity on the center axis is maximum. This directional characteristic has a concentric sensitivity distribution centered on the central axis 0 ° because the arrangement of the thermocouple elements 83 is circular. Here, it is assumed that the optical axis of the Fresnel lens 8e and the center point of the gold black 82 in the thermopile 8b match.

In the case where the Fresnel lens 8e is provided, not only is the temperature-sensitive viewing angle β small, but also it is difficult to sharply sense the temperature at both ends. That is, the temperature sensitive region and the non-temperature sensitive region are clearly separated.

By using the Fresnel lens 8e, radiant heat (infrared rays) from the object to be measured can be efficiently condensed.
Can be narrowed down to ゜. Also silicon, germanium,
Since a polyethylene resin is used instead of a lens that transmits infrared rays with an inorganic material such as barium fluoride or calcium fluoride, molding is easy, thin, light, and inexpensive. Polishing is not required and mass production is easy. When using a Fresnel lens, as a point to be noted, as the angle of view of the incident light beam increases, the shading of the light beam due to the rising surface of the Fresnel lens increases. It is known that the thermopile 8b has a large number of thermocouple elements 83 arranged radially and the hot junction 8 of the thermocouple element 83 is formed.
Since 5 substantially coincides with the optical axis of the Fresnel lens 8e, the sensitivity on the optical axis of the Fresnel lens 8e is maximized, and an output voltage corresponding to the temperature to be measured can be efficiently obtained. In other words, the infrared light passing through the vicinity of the optical axis (center axis) of the Fresnel lens 8e also has a larger light amount, so the thermopile 8b
Combined with the directional characteristics of, the radiant heat from the temperature measurement object can be collected efficiently.

In FIG. 1, reference numeral 9 denotes the food 2 by the heating means 5.
This is a driving means for continuously rotating the temperature detecting means 8 in the vicinity of the cooking chamber 1 from the start to the completion of heating. The driving means 9 determines that the temperature detecting means 8 has a frequency of 2 Hz (that is, 5 Hz).
Equipped with a motor and a pulley so as to swing the head 20 ° at a time around the rotation axis of the cooking table 4 so as to make one reciprocation at 00 ms.
It is connected to the temperature detecting means 8 via a timing belt. The temperature detecting means 8 constantly transmits the temperature of the food 2 to be measured to the temperature distribution means 10 as a voltage signal. By providing the rotating shaft of the temperature detecting means 8 in the vicinity of the cooking chamber 1, the opening provided on the ceiling of the cooking chamber 1 can be kept small.

The temperature distribution means 10 samples the voltage signal transmitted from the temperature detection means 8 every 50 ms.
The temperature distribution is measured using 200 points of temperature data as one screen. This is because if the one-dimensional scanning, which makes one reciprocation at 500 ms, is repeated 20 times, the cooking table 4 also makes one round (= 1).
Since 0 seconds have elapsed), the collected 200 points of temperature data are associated with each pixel of the two-dimensional thermal image.
The temperature distribution detecting means 10 extracts the highest temperature and the lowest temperature of the food 2 from the collected 200 points of temperature data, and outputs them to the control means 11. Temperature data of 200 points is 500
The maximum temperature and the minimum temperature of the food 2 are updated every ms, and are output each time. In other words, a new one in 10 seconds
A configuration in which a two-dimensional thermal image of a screen is obtained. After collecting the two-dimensional thermal image of the first one screen (= after the first 10 seconds), 50
The data is replaced with the latest data every 0 ms (= every 10 temperature data). Thereby, the control means 11
Operation in 10 seconds (= each time the cooking table 4 makes one rotation)
Since the determination can be made quickly instead of a slow determination such as the number of times, the work accuracy of the food 2 is improved.

Here, the temperature detecting means 8 has a configuration in which a thermopile of one element is used, which is rotated and scanned, and a two-dimensional thermal image is obtained by using the rotation of the cooking table 4. May be arranged one-dimensionally to detect a large number of temperature data simultaneously. The driving method of the temperature detecting means 8 by the driving means 9 is not limited to the rotation. For example, a plurality of holes may be provided in a row on the ceiling surface of the cooking chamber 1, and the temperature of the food may be detected from the plurality of holes while the temperature detecting means 8 is horizontally moved.

The drive means 9 and the cut-off means 12 are also used,
When the temperature of the food 2 is not measured, the temperature detecting means 8 is set to 90
゜ It may be one that insulates from the cooking chamber 1 by rotating.

The control means 11 determines whether the minimum temperature of the food 2 transmitted from the temperature distribution detecting means 10 every 500 ms exceeds a predetermined value and the maximum temperature exceeds another predetermined value.
To complete the heating. In addition, uniform heating is achieved by adjusting the heating control amount output from the heating means 5 according to the temperature difference (the highest temperature-the lowest temperature) of the food 2.

For example, when it is desired to continuously heat (keep heat) the food 2 at a constant temperature of 60 ° C. for a long time, the heating control amount P [W] output from the heating means 5 is changed to the heating control amount P [W] = K ₁ (60 ° C.) −average temperature of food 2) −K ₂ (temperature difference [° C.] of food 2) (K ₁ and K ₂ are constants). Thereby, when the whole food 2 is far from 60 ° C. and is low, the heating is strong, while when the temperature difference of the food 2 becomes large, the operation of suppressing the heating can be realized. Of course, by applying PID control or the like including the term of time, unevenness in the temperature of the food 2 and variation in workmanship may be further reduced. Here, K ₁ and k ₂ can be determined by experiments.

Numeral 12 is a blocking means for blocking radiant heat radiated from the food 2 to the temperature detecting means 8 when the food 2 is not heated by the heating means 5, and dirt and vapor scattered from the food 2 adhere to the Fresnel lens. Not configured. Further, the blocking unit prevents the Fresnel lens 8e and the resin case 8a provided in the temperature detecting unit 8 from being deformed by the heat from the heating unit 5 or the food 2.

Although the heat distortion temperature of polyethylene is about 80 ° C., when the temperature of the food 2 is detected by the temperature detecting means 8 at a predetermined temperature or more, the shut-off means 12 reduces the radiant heat radiated from the food 2 to the temperature detecting means 8. It may be configured to shut off.

In the above configuration, the temperature detecting means 8 having a narrow temperature-sensitive visual field is formed because the Fresnel lens 8e efficiently collects the radiant heat radiated from the food 2. Particularly, as a configuration of the thermopile 8b, 100 pairs of thermocouple elements are arranged radially and the hot junction 85 of this thermocouple element is close to the optical axis of the Fresnel lens 8e, so that the sensitivity is centered on the optical axis of the Fresnel lens 8e. Is concentrated. That is, the output of the thermopile is the food 2 on the optical axis of the Fresnel lens 8e.
Has a steep directional characteristic only in a specific portion of Therefore, the temperature of each part of the food 2 can be individually measured instead of the average temperature of the food 2.

In particular, since the condenser lens is composed of polyethylene Fresnel lens 8e, silicon, germanium,
Compared to a lens that polishes an inorganic material that transmits infrared rays, such as barium fluoride and calcium fluoride, molding is easier, thinner, lighter, and less expensive.

Further, by providing the blocking means 12 for blocking radiant heat radiated from the food 2 to the Fresnel lens 8e when the food 2 is not heated, dirt and vapor scattered from the food 2 do not adhere to the Fresnel lens 8e. Further, the Fresnel lens 8e is not deformed by the heat from the heating means 5 or the food 2. Therefore, the temperature of the food 2 measured by the temperature detecting means 8 can be always accurately measured.

Further, the temperature distribution measuring means 10 grasps the food 2 in the form of a two-dimensional thermal image based on a plurality of outputs from the temperature measuring means 8 which is rotated and moved by the driving means 9, and obtains the maximum temperature of the food 2 caused by heating. By providing the control means 11 which immediately outputs the change of the minimum temperature to the control means 11 and controls the heating means 5 in accordance with the output of the temperature distribution measuring means 10, the temperature unevenness of the food 2, the maximum temperature, the minimum Fine heating control according to the temperature is realized. As a result, without being affected by the type, shape, number, placement, etc. of the food 2,
Further, there is an effect that automatic cooking can be performed without variation in workmanship by fine-grained heating control according to the temperature unevenness of the food 2.

[0048]

According to the present invention as described above, the following effects can be obtained.

(1) Since the sensitivity of the thermopile is concentrated around the optical axis of the condensing lens, the temperature of each part of the food can be individually measured, so that it is influenced by the type, shape, number, placement, etc. of the food. Automatic cooking without unevenness in workmanship can be achieved by heating according to the temperature of each part of the food without the need for heating.

[0050]

[0051]

[0052]

(2) Since the heating means and the control means control in consideration of the difference between the food temperature and the set temperature and the temperature difference of the food being heated, quick and fine automatic adjustment can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a cooking device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a temperature detecting means in the embodiment.

FIG. 3 is a plan view showing a main part of the thermopile in the embodiment.

FIG. 4 is a diagram showing directivity characteristics of a temperature detecting unit in the embodiment.

FIG. 5 is a block diagram showing a configuration of a conventional cooking device.

FIG. 6 is a sectional view showing a configuration of a temperature detecting means in the embodiment.

FIG. 7 is a diagram showing a temperature-sensitive field of view of a temperature detecting unit in the embodiment.

FIG. 8 is a plan view showing a main part of the thermopile in the embodiment.

FIG. 9 is a view showing the directional characteristics of the temperature detecting means in the embodiment.

[Explanation of symbols]

 2 Food 5 Heating means 8 Temperature detecting means 8b Thermopile 8e Condensing lens (Fresnel lens) 9 Driving means 10 Temperature distribution measuring means 11 Control means 12 Blocking means

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideki Terasawa 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-24777 (JP, A) JP-A-2-2 196933 (JP, A) JP-A-3-164618 (JP, A) JP-A-5-87344 (JP, A) JP-A-58-158202 (JP, U) JP-A-53-158964 (JP, U) 55-135942 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F24C 7/02 330 F24C 7/02 320

Claims (1)

(57) [Claims] 1. A heating means for heating food, a condenser lens for condensing radiant heat radiated from the food, and a radial multi-pair for converting the radiant heat from the food collected by the condenser lens to thermoelectric conversion. A thermopile in which thermocouple elements are arranged, and control means for controlling the heating means in accordance with the output of the thermopile, wherein the thermopile is disposed such that its hot junction substantially coincides with the optical axis of the condenser lens. And
The control formula is the heating control amount (W) = K1 (T-average temperature of food)-K2 (difference in temperature of food) T: Set temperature (° C), K1, K2: Control hand according to constant
A cooking device in which the stage controls the heating means .