JPH0410384A - High-frequency heating device - Google Patents

Abstract

PURPOSE:To ensure the stale thawing of a frozen food by using a support fitting for firmly fixing a wave detection means so formed as to be integral with an antenna near the opening of a heating chamber wall and used for detecting a DC wave received with the antenna. CONSTITUTION:A high frequency not absorbed by a food 1 in a heating chamber 2 leaks at an opening 10, is detected with an antenna 6 and detected with a wave detection means 7. In this case, the wave detection means 7 is firmly fixed with a support fitting 11 using solder, thereby eliminating high-frequency coupling between the opening 10 and antenna 6, or the occurrence of a mechanical vibration in detecting the leak current and component dislocation during transportation. According to the aforesaid construction, a signal can be stably detected, and automated thawing can be easily embodied.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a high-frequency heating device for achieving automated defrosting of food products.

BACKGROUND OF THE INVENTION Conventionally, as an example of automating the thawing state of this type of high-frequency heating device (hereinafter referred to as a microwave oven), there has been an example of automating the thawing state of food as seen in Japanese Patent Application Laid-Open No. 59-207595. This was indirectly understood from the relationship between the temperature dependence of the dielectric loss and the detected output signal of the detection means in the oscillation frequency band of the high-frequency radiation means. That is, the seventh
As shown in the figure, 1 is food, 2 is a heating chamber, 3 is a high frequency radiation means (hereinafter referred to as a magtron), 4 is a transformer for operating the magnetron 3, 5 is a cooling fan for cooling the magnetron 3, 6 is a needle-shaped antenna provided inside the heating chamber. 7 is a detection means, 8 is a drive means for varying the high frequency power of the magnetron 3, and 9 is a control means for controlling the drive means 8 according to a signal from the detection means to adjust the output of the high frequency power.

As a means of grasping the amount of load on food 1, when food 1 is in the state of ice crystals at about -18°C, the dielectric loss is small and the high frequency power absorbed by food 1 is small, so it is relatively detected by an antenna. The signal becomes larger. This detected signal has an inversely proportional relationship with the load amount of the food 1 in the heating chamber 2, and the output of the magnetron 3 is controlled by determining the load amount based on the value of the signal.

Thawing of food was achieved through such control.

Problems to be Solved by the Invention However, in the above configuration, the antenna 6
Since the antenna 6 is placed inside the heating chamber, there is a problem in that it is difficult to manage high frequency variations in the signal line connecting the antenna 6 and the detection means 7.

Furthermore, when an opening is provided in the heating chamber 2 and the radio waves leaking from the opening are detected by the detection means 7 provided near the opening, the high frequency coupling may not be fixed depending on the way the heating chamber is supported, so the detection means 7 There were times when the signal values varied greatly.

Therefore, an object of the present invention is to realize stable thawing of food with a simple configuration.

Means for Solving the Problems In order to solve the above problems, the present invention provides an antenna provided near the opening made in the wall of the heating chamber, and a detection means that is integrated with the antenna and performs DC detection of radio waves received by the antenna. , a support that supports the detection means and is made of a conductor; and the support is configured to fixedly support the detection means.

According to the present invention, radio waves that are not absorbed by the food leak through the openings made in the heating chamber, and the detection means fixed with the support can realize thawing in a microwave oven.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings. Note that the component parts are the same as in the conventional example, and the same parts are given the same numbers.

FIG. 1 is a partial structural perspective view of a high-frequency heating device according to an embodiment of the present invention when a detection means 7 is attached to an opening formed on the upper wall of a heating chamber 2. FIG. 10 is an aperture 10 whose shape is elongated and whose dimensions are determined by the oscillation frequency of the magnetron 3 (
This is shorter than the 174 wavelengths (approximately 30) of the 2450M wavelength. (For example, 15) This is the 5 which is supplied into the heating chamber 2.
This is because the large output of 0.00 watts does not leak from the aperture 10, and only a minute amount of radio waves are leaked for detection. Furthermore, by making the shape into an elongated hole, the detecting means 7 detects minute leaking radio waves, unlike previous needle-shaped antennas that detect at one point. This allows stable signal detection regardless of the

11 is a conductive support for supporting the detection means 7;
2 is solder, which fixes the detection means 7 at four locations to prevent positional deviation.

FIG. 2 is an overall configuration diagram of a high-frequency heating device according to an embodiment of the present invention, as seen from the top.

2 is a heating chamber, 3 is a magnetron, 4 is a transformer for operating the magnetron 3, 5 is a cooling fan that cools the magnetron 3, and 6 is an antenna, which is shorter than the 174 wavelength of the oscillation frequency (2450 MHz) of the magnetron 3. It is integrated with the detection means. 7 is a detection means, 8 is a drive means for varying the high frequency power of the magnetron 3, 9
13 is a control means (a microcomputer in the present invention) which controls the drive means 8 according to the signal from the detection means and adjusts the output of high-frequency power; 13 is a dielectric between the aperture 1o and the detection means 7; is provided to prevent the detection means from being contaminated by food in the heating chamber 2.

With these configurations, high-frequency waves that are not absorbed by the food in the heating chamber leak through the openings, are received by the antenna 6, and are detected by the detection means 7.
The wave is detected by

FIG. 3 is a circuit diagram of the detection means 7 for detecting the oscillation signal of the magnetron 3. 14 is a 50 ohm resistor, 15 is a detection diode (for example, a Schottky barrier diode), 16.17 is a resistor, and 18 is a capacitor. These detect the high frequency power that is not absorbed by the food in the oscillation frequency band of the magnetron 3, and the voltage VS DC detection is performed as

FIG. 4 is a diagram in which the detection means 7 is composed of a microstrip line.

Copper foil patterns 20, 21, 22, 23, 24 are etched on a dielectric double-sided copper-clad substrate 19 having a certain dielectric constant ER. The copper foil section 20 forms the 50 ohm in Figure 3 14, and the section 23, 24 and 19
The ground plane formed on the opposite side of the board is through hole 2.
5 is conductive, and 26, 27, 28, and 29 are supported by the support 11 and are electrically connected to the ground plane similarly formed on the opposite side of the board through holes.

The antenna 6 is also formed of a copper foil on the opposite side of the substrate 19 and is integrated with the detection means, and the copper foil portion 20 is similarly electrically connected to the copper foil portion 30 through a through hole 30.

By configuring the detection means 7 on the microstrip line, it is easy to optimally design the length of the line according to the frequency band to be detected, and since this is done by etching, dimensional accuracy is improved. be.

FIG. 5 is a characteristic diagram showing the signal level of the detection voltage Vs with respect to the weight of the food (frozen minced meat) immediately after the start of thawing. This figure shows that there is a large difference in the detected voltage immediately after the start of defrosting, depending on the weight of the food. This is because when the weight of the food is small, less high frequency waves are absorbed and relatively more high frequency waves are detected by the antenna 6.

The relationship shown in FIG. 5 can be maintained stably by firmly fixing the detection means 7 to the support 11 by soldering. Mechanical vibrations and
This is because positional displacement does not occur during transportation.

In the present invention, the detection means 7 and the aperture 10 are provided on the upper surface of the heating chamber, but they may be provided on the lower surface of the heating chamber, but are not limited to the first embodiment of the present invention.

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

The antenna installed near the opening in the heating chamber wall and the detection means supported by a support made of a conductor are fixed by soldering to emit high frequency waves in the frequency band of the high frequency radiation means, so the microwave oven external vibrations, shock vibrations,
Since there is no positional shift of the detection means during transportation, stable signal detection is achieved and anyone can easily automate defrosting without failure.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of a high-frequency heating device according to an embodiment of the present invention when a detection means is attached to the top surface of the heating chamber, FIG. 2 is an overall configuration diagram of the device, and FIG. 3 is a diagram of the same device. A circuit diagram of the detection means, Fig. 4 is a sectional view of the detection means of the same device configured on a substrate, Fig. 5 is a characteristic diagram of the signal of the detection means with respect to food weight when the device is thawed, and Fig. 6 is a conventional diagram. FIG. 2 is a main body configuration diagram of a high-frequency heating device. ■...Food, 2...Heating chamber, 3...
... High frequency radiation means, 6 ... Antenna, 7.
...Detection means, 9...Control means, 10.
...Opening part, 11... Support tool, 12...
...Solder, 13...Dielectric. Name of agent: Patent attorney Shigetaka Awano Haka1 person 2・-1a
glue! Figure Figure 30ri5ρO 1t Ct)

Claims (1)

[Claims] A heating chamber for taking food in and out, a high frequency radiation means for feeding high frequency power into the heating chamber, a control means for controlling the high frequency radiation means, an antenna provided near an opening made in a wall of the heating chamber, and the antenna. a detection means that is integrated with the antenna and detects a direct current of radio waves received by the antenna; a support that supports the detection means and is made of a conductor; and a dielectric interposed between the opening and the detection means. The high-frequency heating device comprises a high-frequency heating device in which the detection means is fixedly supported on the support, and the control means is controlled based on a signal detected by the detection means.