JPH03210786A - High frequency heating device - Google Patents

Abstract

PURPOSE:To obtain stable detection output with the dispersion of the fitting position of a detection circuit lessened by forming a detection circuit, for detecting a radiation electric wave for heating via an antenna, with an insulation plate, and also providing a stopper for regulating this structure body position. CONSTITUTION:A high frequency heating device for heating food is controlled according to a detected result with a radiation electric wave for heating detected by an antenna 1 and a detection circuit. The detection circuit is formed with an insulation body, and the fitting position of a detection circuit structure body 8 is regulated by a stopper 10 to restrain the dispersion of the fitting position. Consequently the effect of an outer leakage electric wave is alway made constant the distance between outer metal and the structure body 8 is settled to eliminate the increase and decrease of impedance variation or floating capacity, and detection output is stabilized to make good heating control.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high frequency heating device that automatically detects the condition of food and controls equipment operation.

BACKGROUND OF THE INVENTION In recent years, high-frequency heating devices that automatically detect the condition of food and control device operations are required to accurately detect the condition of the food.

Conventionally, this type of high-frequency heating device was disclosed in Japanese Patent Application Laid-Open No. 69-2075.
As shown in Publication No. 95 or Japanese Patent Application Laid-open No. 59-207596, high-frequency radio waves are irradiated into a heating chamber, and the reflected radio wave signal from the food changes due to the change in dielectric constant of the food as the degree of heating of the food increases. This was used to detect the condition of food and control equipment operations.

Problems to be Solved by the Invention In such conventional high-frequency heating devices, in order to detect the state of food in the heating chamber, an antenna and a detection circuit are used to monitor the state of radio waves in the heating chamber. When using a detector circuit, if the position of the detector circuit is not fixed, it will be affected by the electric field distribution in the external field and generate noise, and the impedance will change depending on the distance to the metal part, and the detection output will fluctuate, making it difficult to determine the condition of the food. The problem was that accurate detection was not possible.

The present invention has been made to solve the above-mentioned problems, and aims to suppress variations in the mounting position of the detection circuit, extract the detection output with high accuracy, and enable stable detection of the state of food.

Means for Solving the Problems In order to achieve the above object, the present invention provides that a detection circuit is formed on an insulating plate, and a stopper is provided for fixing the position of the detection circuit structure integrated with the insulating plate. It is used as a solution.

Effects of the present invention Due to the problem solving means described above, the mounting of the detection circuit has little variation in position, is always influenced by external leakage radio waves other than the radio waves detected by the antenna, and also has the advantage that the detection circuit and the external Since the distance to the metal is also constant, there is no change in impedance or increase or decrease in stray capacitance, and stable detection output can be obtained.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

As shown in the figure, the antenna 1 detects the state of radio waves in the heating chamber 2, and is made up of a bolt 3 that passes through a hole 5 in the top surface 4 of the heating chamber. Through the external space 6 and the insulating internal spacer 7, the detection circuit arrangement 8
It penetrates through and is fixed onto the detection circuit structure 8 with a nut 9. Here, a stopper 10 attached to the top surface 4 of the heating chamber and made of an insulator plays the role of fixing the detection circuit assembly 8 when the nut 9 is tightened. An insulating plate 11 is interposed to maintain insulation between the head of the port (antenna 1) 3 and the top surface 4 of the heating chamber, and a hole 13 is also provided in the ground plane 12 of the detection circuit assembly 8. The detection circuit structure 8 is constructed by applying copper foil to both sides of an insulating plate 14 made of tetrafluoroethylene resin or glass epoxy resin, and one side is used as a signal plane 16 and the other side is used as a ground plane 12. ing. The nut 9 is conductive together with the bolt (antenna 1) 3, and is tightened so as to be in close contact with the signal surface 15.

Next, as shown in FIG. 2, the radio waves emitted from the radio wave emitter 16 pass through the waveguide 17 and heat the food 18 in the heating chamber 2. The state of the radio waves in the heating chamber 2 is detected by the antenna 1,
The detection circuit component 8 detects the direct current, and this detection output is guided to the controller 19, which in turn
Control equipment operations such as

To explain the operation in the above configuration, the radio waves emitted from the radio wave emitting section 16 heat and cook the food 18 in the heating chamber 2. Figure 3 is a characteristic diagram showing the time change of the detection output v8 as cooking progresses.As the frozen food is heated, a
The amplitude and level change characteristically at point b and point b at the start of boiling. The controller 19 determines the inflection point of this detection output v8 and the equation 1.
The food 18 in the heating chamber 2 is heated and cooked by controlling the operations of various devices such as the radio wave emitting section 16 based on the amplitude change having the frequency component of the band according to a control algorithm determined at the time of design or setting.

At this time, since a stopper 10 is provided for fixing the position of the detection circuit component 8, the detection circuit component 8 can be mounted with little variation in position, and the influence of external leakage radio waves other than the radio waves detected by the antenna 1 is always avoided. In addition, the distance between the detection circuit component 8 and external metal, such as the top surface of the heating chamber 4, becomes constant, and there is no change in impedance or increase or decrease in stray capacitance, and a stable detection output is obtained. The condition of the food 18 can be detected with high accuracy. Therefore, the operation of various devices such as the radio wave emitting section 16 is controlled by this detection output, and the food 1
You can cook the best food for B.

Effects of the Invention As is clear from the above embodiments, according to the present invention, it is easy to suppress variations in the mounting position of the detection circuit component, stabilize the influence of external noise, and prevent changes due to the positional relationship with external metal. It is possible to stabilize the impedance that tends to occur, and the detection output can be extracted with high precision, so the state of the food can be detected extremely stably.This detection output can be used to control the operation of various equipment such as the radio wave emitting part, and provide the optimal heating for the food. I can cook.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main parts of a high-frequency heating device according to an embodiment of the present invention, Fig. 2 is a sectional view of the same high-frequency heating device, and Fig. 3 is a time period of a detection signal as cooking progresses in the same high-frequency heating device. It is a change characteristic diagram. 1...Antenna, 2...Heating chamber, 8.
. . . Detection circuit groove structure, 1o . . . Stopper, 16 . . . Radio wave emitting section, 18 .

Claims (1)

[Claims] a heating chamber that stores food, a radio wave radiator that emits radio waves to heat the food, an antenna that detects the state of radio waves in the heating chamber, and a detection circuit that detects the radio waves detected by the antenna; a controller for controlling device operation according to the output of the detection circuit, the detection circuit being formed on an insulating plate, and a stopper for fixing the position of the detection circuit component. .