JPS59183221A - High frequency heating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to non-contact temperature measurement of cooking appliances, and in particular to detection of the position of an infrared temperature detector and a temperature measuring element in a rotating mounting type microwave oven. It's about configuration.

Structure of the conventional example and its problems In a conventional microwave oven having an infrared detector, for example, as shown in Japanese Utility Model Application Publication No. 57-21903, the infrared detector is placed in a position where its viewing area is at the center of the rotating mounting table. As shown in Japanese Patent Application Publication No. 56-69794, a microcomputer is used to control the position of the infrared detector so that the field of view of the infrared detector always includes the food. be.

However, the former method has the following problems. That is, in general, the electric field strength distribution in the heating chamber of a microwave oven is not uniform, and the electric field strength is high in the part indicated by a in FIG. 1, and the electric field strength is low in the part indicated by b. In other words, there is a standing wave. In a rotating microwave oven (Figure 2), the food passes through standing waves in this way, and the high-frequency energy is effectively absorbed by the food F as a time integral. That's what I do. Therefore, in a configuration in which the field of view for infrared detection looks into the center of the heating chamber 5, (1) the temperature of the food F can be measured at the point where the food F does not move in the electric field, that is, the center of the rotary mounting table; Food F
It is not possible to measure the average temperature of

(2) Generally, the electric field distribution of a microwave oven tends to be weak at the center, so if the temperature is measured at the center, as shown in FIG. 3, the completion time will be delayed if the food F or the container is small. (Generally, in a rotating microwave oven, food F is usually placed off-center.

(3) For a large food F (for example, reheating oyakodon), if the food F is placed in the center and the infrared temperature is detected at the center, the standing wave distribution in the heating chamber will not be improved, as shown in Figure 3. The temperature of the center C shown in is lower than the temperature of the peripheral part d, and it is difficult to control the temperature rise of the entire food F by measuring the temperature of the center. Above (1),
(21, The drawback of (3) is that an infrared detection method that takes advantage of the characteristics of the rotational mounting method has not been developed.8 In addition, in the latter of the conventional examples, food F is tracked by a microcomputer. In addition, when the temperature inside the room becomes high, it becomes difficult to determine whether the infrared rays are emitted from the food F or the infrared rays generated by heating the heating chamber 5, making it difficult to accurately detect the food temperature. There is a problem.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to effectively and reliably detect the temperature of food using infrared rays in a rotary mounting type microwave oven.

Structure of the Invention In order to achieve the above object, the high frequency heating device of the present invention has an infrared detection element mounted eccentrically from the center of the heating chamber.
Also, a mark indicating the food placement position is displayed on the rotating table, and a signal is sent to notify that the food placement position is directly below the infrared detection element, and measurements are taken only when the food placement position is directly below the infrared detection element. It is configured to perform infrared temperature measurement at a position where the average temperature of food in the heating chamber can be measured, which is a feature of the rotating mounting method, and has the effect of achieving efficient and good temperature control of food. It is something that you have.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 5, the microwave excited by the magnetron 3 is guided into the heating chamber 5 by the waveguide 4, and is absorbed by the food F placed on the rotating table 1 in the heating chamber 5. Food F is heated. The surface temperature of the heated food F is compensated for as a change in the amount of infrared radiation by an infrared sensor element 7 (for example, a pyroelectric infrared sensor) provided outside the heating chamber ceiling hole 6 shown in FIG.

The above heating chamber ceiling hole is located between the center of the rotating mounting table 1 and the rotating mounting table 1.
It is hung in a position overlooking the concentric circumference on the rotary mounting table 1 whose radius is the length of the line segment connecting one point on the end face of the rotary mounting table 1. In FIG. 6, it is approximately l = 62.

FIG. 7 is a diagram showing the configuration of the rotary mounting table 1.

On the surface thereof, a food F placement position mark 8 is printed in a circular shape, or as shown in FIG. 8, it is indicated by a shallow circular recess 8a. The positional relationship between the center of the recessed portion 8a and the rotary mounting table 1 is 12=1. The center m of the recessed portion 8a is looked down upon by the infrared sensor element 7.

Further, a protrusion 9 made of a magnetic material is provided on the back surface of the rotary mounting table 1. This protrusion 9 is made shorter than the other protrusions 18. The bottom surface of the heating chamber 5 is made of a non-magnetic material, and a magnetic detection element 1° such as a Hall element or a proximity sensor is installed on the outer bottom surface. When the rotary mounting table 1 rotates and the protrusion 9 of the magnetic material approaches the magnetic detection element 10, a signal is sent from the magnetic detection element 10. At this time, the positional relationship between the protrusion 9, the magnetic detection element 10, and the mounting position mark 8 is taken into consideration so that the mounting position mark 8 on the surface of the rotary mounting table 1 is located directly below the heating chamber ceiling hole 6.

The rotary mounting table 1 is rotated by the rotational force transmitted by the shaft passing through the bottom of the heating chamber 5, and the rotating shaft 11 and the rotary mounting table 1 are fitted together (FIG. 1o). In this case, even without using the magnetic detection element 1o as described above,
It is also possible to substitute this by providing a microswitch 12 that detects the rotation angle of the shaft near the rotation shaft 11 outside the bottom surface of the heating chamber. '11, whose configuration is shown in Figure 10.
The figure is an embodiment of a block diagram of the configuration of an electric circuit according to the present invention. The signal from the infrared sensor element 7 is amplified through an amplifier 13, passed through a gate 14 that is opened and closed by the signal from the magnetic detection element 10, and is sent to a microcomputer 15.
The signal is processed internally. When the signal from the magnetic detection element 10 should not be output, that is, when the food F has not reached the lower part of the heating chamber ceiling hole 6, the gate 1
4 is closed, and the signal from the infrared sensor element 7 is not taken into the microcomputer 15.

The signal from the magnetic detection element 10 is also sent to the drive mechanism 17 of the Jawarter 16, and the heating chamber ceiling hole 6 is opened only when the food F is located at the lower part of the heating chamber ceiling hole 6. . FIG. 12 shows a timing diagram showing the relationship between each signal and the operation of the drive mechanism 1 for the shaft lid 16. The microcomputer 150 input signal indicates that it is active only while the gate signal is output.

Further, as shown in FIG. 7, three or more protrusions 18 may be provided on the back surface of the rotary mounting table 1 so as to surround the protrusions 9 of the magnetic material, or one of the three protrusions 18 may be It is also possible to adopt a configuration in which the protrusion is made of a magnetic material. In this way, according to this embodiment, the conventional drawback that the average temperature of the food F cannot be measured can be improved. That is, infrared sensing is performed at a location other than the center of the heating chamber 5 to measure the temperature rise as a result of the food F moving through the standing wave distribution and receiving average microwave energy. Therefore, rather than measuring the center point, food F
will measure a more average temperature.

In addition, it is easy to use because the position where the food is placed on the rotating table 1 is clearly indicated.Moreover, in the rotary placing system, the food F is generally not placed in the center, so the position where the food F is placed is clearly indicated. There is no sense in choosing something other than the center.

Furthermore, by configuring the measurement hole to be opened only during infrared measurement, the probability that food particles or the like will enter through the detection hole and contaminate the detector can be extremely reduced.

The back of the rotating mounting table has three or more protrusions, and the height of the protrusion for position detection is lower than the height of the other protrusions, or one of the three protrusions has a protrusion for position detection. By making the rotary mounting table also function as a rotary mounting table, stability will not be compromised even if the rotary mounting table is taken out and placed.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) Since the food temperature is measured at the point where the food receives energy on average, the average food temperature can be measured.

(2) The position of food and the timing of temperature measurement can be easily synchronized using a magnetic switch.

(3) A stable rotating mounting table can be realized by making the height of the position detection projection lower than other projections.

(4) Since the measurement hole is opened only when food is directly below the sensing element, the probability that foreign matter will enter and contaminate the sensing element is extremely small.

[Brief explanation of drawings]

Figure 1 is a diagram showing the electric field distribution inside the heating chamber, Figure 2 is a diagram showing the configuration of a conventional microwave oven with an infrared element, Figure 3 is a diagram showing the relationship between food position in the heating chamber and completion time, and Figure 4 is a diagram showing the relationship between food position in the heating chamber and completion time. Diagrams showing the temperature distribution of food - Figure 5 is a partially cutaway front view of a microwave oven, Figure 6 is a partially cutaway front view of a microwave oven that is an embodiment of the present invention, and Figures 7a and b 8 is a sectional view of the quadriturn mounting table, FIG. 9 is a sectional view of the lower part of the heating chamber, and FIG. 10 is a bottom penetrating type according to another embodiment of the present invention. 11 is a block diagram of a circuit configuration of a microwave oven according to an embodiment of the present invention, and FIG. 12 is a timing chart of signals of the circuit. 1...Food placement table, 3...Magnetron, 5...Heating chamber, 6...Heating chamber ceiling hole,
7...Infrared sensor element, 8...Position mark, 9...Magnetic material protrusion, 1o...Magnetic detection element, 18...Protrusion Department. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 〇 Figure 3 Figure 6 f8 Figure 8

Claims (4)

[Claims] (1) A heating chamber in which food is placed, a high-frequency generating means for heating the food in the heating chamber, a circular rotating food placing table in the heating chamber, and a surface of the food placing table on which the food is placed. an infrared detection device that detects infrared rays from the food, which displays the placement position at a location other than the center thereof, and is provided at a position where the rotation locus of the placement position is viewed directly below the ceiling of the heating chamber; A high-frequency heating device comprising: means for blocking infrared rays from entering an infrared detecting device through an opening; and a means for detecting that the food placement position has reached directly below the infrared detecting device. (2) A magnetic protrusion is provided on the back of the food placement position display section of the food placement table, the bottom of the heating chamber is made of non-magnetic material, and the magnetic detection element is installed as an infrared detection device at the outside bottom of the heating chamber. The high-frequency heating device according to claim 1, which is installed at a position directly below. (3) The high-frequency heating device according to claim 1, wherein protrusions higher than the protrusions of the magnetic material are arranged concentrically on a rotary mounting table having protrusions of the magnetic material on the back surface thereof. (4) The high-frequency heating device according to claim 1, wherein the shaft cover is opened only when the mark approaches directly below the sensor hole.