JPS6359235B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a microwave oven, a microwave oven, and other cooking appliances that perform microwave heating. The present invention relates to a cooker that performs microwave heating by supplying microwave power.

[Prior art]

In microwave ovens, microwave ovens, and the like that use microwave oscillators to microwave food to be cooked, how to eliminate uneven heating is an important issue. Heating unevenness during microwave heating is
To varying degrees, standing waves occur when microwaves in a certain mode are applied to the food to be cooked, or when microwaves are only supplied to a portion of the food to be cooked. Therefore,
In order to eliminate such uneven heating, it is necessary to prevent microwaves in a fixed mode from being supplied to the food to be cooked, in other words to prevent standing waves from being generated, or to prevent the microwaves from being applied to the entire food to be cooked. It is best to ensure that it is supplied evenly. For this purpose, for example, a stirrer, a turntable, etc. are used, or both are used in combination. That is,
A stirrer mainly stirs and reflects microwaves supplied through a waveguide, converting them into a complex mode to prevent the generation of standing waves, and a turntable rotates the food to be cooked. By doing so, microwaves can be evenly supplied to the entire food to be cooked.

However, installing a stirrer or turntable in a cooker requires a mechanism, power, etc. to rotate them, which complicates the structure of the cooker, increases manufacturing costs, and increases the incidence of failure. There are problems such as:

For example, a cooking device is being considered in which microwaves emitted from a magnetron are guided to a T-shaped antenna via a converter having a cylindrical resonance mode, and then radiated toward the food to be cooked above the antenna. .

[Problems that the invention attempts to solve]

However, in such a cooking device, the strongest electric field occurs in the direction perpendicular to the axial length of the antenna, and it is unlikely that the electric field in the same direction will become quite strong even in the cooking chamber where the food to be cooked is stored. This is unavoidable, and therefore standing waves are likely to occur. When standing waves occur, they are more likely to be affected when the load is light, that is, when the amount of food to be cooked is small, or when the food to be cooked is flat, and therefore good cooking results cannot be obtained. Problems such as this arise.

[Means for solving problems]

The present invention has been made in view of the above-mentioned circumstances, and the present invention introduces microwaves emitted from a microwave oscillator to an antenna via a converter having a cylindrical resonance mode, and then directs the microwaves to the antenna, which is located above the antenna. The purpose of the present invention is to provide a cooking device that can eliminate uneven heating by dispersing heat using a resonant element provided on a food table, without having to use moving parts such as a stirrer or a turntable that complicate the structure of the cooking device. do.

The present invention provides a microwave oscillation device, a conversion section that converts the microwave emitted from the microwave oscillation device into a cylindrical resonance mode, and a microwave coupled to the microwave oscillation device above the microwave oscillation device. It is characterized by comprising an antenna that radiates waves, a food table provided above the antenna and on which the food to be cooked is placed, and a microwave resonant element provided on the food table. do.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a partially sectional elevational view showing the configuration of the main parts of the cooking device according to the present invention.

Outside the bottom plate 12 of the cooking chamber 1 is a magnetron 2, which is a microwave oscillation device, and its cylindrical antenna (hereinafter referred to as magnetron antenna) 21.
It is attached in a state where it protrudes into the cooking chamber 1.

On the other hand, inside the bottom plate 12 of the cooking chamber 1, a covered cylindrical converter 3 is connected to the antenna 2 of the magnetron 2.
It is attached concentrically with. A small hole 31 is formed at a position slightly away from the center of the lid of the converter 3 toward the outer circumference. An antenna support member 5 made of synthetic resin is fitted into the small hole 31, and a leg portion 41 of the T-shaped antenna 4 is inserted and fixed into the antenna support member 5. On the other hand, the horizontal portion 42 of the antenna 4 has an antenna length of 1/2 wavelength of the microwave generated by the magnetron 2.

Support stands 8, 8 are attached to the portions of the side plates 11, 11 of the cooking chamber 1 at a height slightly higher than the horizontal portion 42 of the antenna 4 on the inside of the cooking chamber 1. A ceramic food placing table 6 on which a food to be cooked 7 is placed is supported.

FIG. 2 is a plan view showing the structure of the food placing table 6. As shown in FIG. The food table 6 uses a ceramic plate as described above, and a large number of resonant elements 9 are mounted on the surface of the ceramic plate.
is provided. These resonant elements 9, 9...
In this example, a thin copper plate having a length of 1/2 wavelength of the microwave emitted by the magnetron 2 is placed on a food table with its length direction parallel to the length direction of the horizontal part 42 of the antenna 4 (the axial length direction of the antenna 4). 6, as shown in FIG.
It was pasted to form a letter-shaped pattern.

Note that the material of the resonant element 9 may be aluminum, etc.
Further, instead of pasting a thin plate, a bar material such as copper or aluminum may be embedded in the food placement table 6. Furthermore, the arrangement of the resonant elements 9 is not limited to the pattern shown in FIG. 2, but may also be freely arranged in other patterns.

The operation of the present invention device configured as above will be explained below.

When cooking food using the inventive device, the food to be cooked 7 is placed on the food table 6 and the magnetron 2 is driven. Microwaves emitted from the magnetron 2 are guided from the magnetron antenna 21 to the leg portion 41 of the antenna 4 and radiated from the horizontal portion 42. In the microwave radiation pattern from the antenna 4 at this time, as shown in FIG. 2, the electric field is strongest in the direction . Therefore, as described above, in the past, the electric field in this direction was quite strong even within the cooking chamber 1, causing standing waves to be generated. However, in the present invention, the antenna 4
Most of the microwaves emitted from the horizontal part 42 are used to heat the food to be cooked 7 placed on the food table 6, but some of them are used to heat the food to be cooked 7 placed on the food table 6. is coupled to the resonant element 9 and sequentially transmits energy to other resonant elements 9, 9, . . . Therefore, at this time, when the food to be cooked 7 is placed on the resonant element 9, heating is promoted by the electric field energy involved in the coupling of microwaves between the resonant elements 9, 9, . Therefore, the food to be cooked 7 is sufficiently heated from the bottom direction.

The energy transmission method of the present invention described above is based on the same principle as a bandpass filter used in the communication field, but it does not require the same level of precision as a bandpass filter, and is based on changes in the load impedance of the magnetron 2. The accuracy may be such that the amount of microwave coupling between the resonant elements 9, 9 differs depending on the relationship. Further, the length of the resonant element 9 may be 1/2 wavelength of the microwave emitted by the magnetron 2,
The number, arrangement pattern, etc. can be freely set depending on the size of the cooking chamber 1 and the food table 6.

〔effect〕

As described in detail above, in the cooker according to the present invention, microwaves are diffused by the resonant element provided on the food table on which the food to be cooked is placed. Therefore, there is less risk of standing waves occurring, so the food to be cooked is not only heated evenly, but also microwave heating is performed from the bottom of the food to be cooked, so the food to be cooked is evenly heated. Efficient microwave heating becomes possible.

In addition, the length of the resonant element used is 1/2 of the microwave
Since the wavelength is set parallel to the antenna axis direction, the diffusion effect of the microwave becomes more pronounced. Furthermore, since the resonant element has a simple structure in which a thin copper or aluminum plate is adhered to the food table or a bar is embedded, the structure is extremely simple and the cost is low.

[Brief explanation of drawings]

The drawings show embodiments of the present invention.
The figure is a partial cross-sectional elevation view showing the configuration of the main parts of the cooking device according to the present invention, FIG. 2 is a plan view showing the configuration of the food placing table, and FIG. . 1... Cooking chamber, 2... Magnetron, 3... Conversion unit, 4... Antenna, 6... Food mounting table, 7...
... Food to be cooked, 9... Resonance element, 21... Magnetron antenna.

Claims (1)

[Scope of Claims] 1. A microwave oscillation device; a conversion section that converts the microwave emitted from the microwave oscillation device into a cylindrical resonance mode; An antenna that radiates microwaves upward, a food table provided above the antenna and on which a food to be cooked is placed, and a microwave resonant element provided on the food table. A cooker featuring: 2. The cooking appliance according to claim 1, wherein the length of the resonant element is 1/2 wavelength of the microwave emitted by the microwave oscillation device. 3. The cooking device according to claim 1, wherein the resonant element is provided on the food table with its length direction parallel to the axial direction of the antenna. 4. The cooking device according to claim 1, wherein the resonant element is a thin plate of copper or aluminum attached to the food table. 5. The cooking device according to claim 1, wherein the resonant element is a copper or aluminum bar embedded in the food table.