JPS6260797B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-frequency heating device that heats an object to be heated such as food using high-frequency energy.
In particular, this invention relates to an improvement in the radio wave leakage prevention mechanism provided at the door periphery.

Conventionally, as a means to prevent the leakage of the fundamental wave of the heating frequency (e.g. 2450 MHz) and the leakage of the second harmonic component, Publication of Utility Model Publication No. 49-31807 describes a method of λ/4 (λ: of the heating frequency) for preventing leakage of the fundamental wave. free-space wavelength) and a λ/8 groove for preventing second harmonic leakage.
It has been proposed that the grooves are provided at different depths, but in this case, both grooves are provided at different positions, resulting in a complicated structure and does not meet the following requirements.

In other words, small, multi-functional electronic components such as ICs and microcomputers have been incorporated into the control circuits of high-frequency heating equipment, making it possible to simplify and reduce the thickness of the operation panel. There is a demand for thin doors that can be removed.

Therefore, the present invention provides a radio wave attenuation cavity with one entrance by arranging the fundamental wave channel groove and the second harmonic channel groove in opposite directions, and provides a radio wave attenuation cavity with a door that satisfies the above requirements. The purpose is to provide a heating device.

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an external view showing an example of the high frequency heating device of the present invention. 1 is an outer box, 2 is a door, and 3 is an operation panel whose thickness is balanced with the thickness of the door 2. Although the operation panel 3 can be changed in various ways depending on the application, the case of automatic heating will be explained as an example.
4 is a display device that shows high frequency output, remaining heating time, etc., 5 is a menu selection button that determines the optimal heating pattern for each menu, 6 is a finish adjustment knob that allows you to select the degree of finish according to your preference, and 7 is when to start heating. 8 is the heating button to press, and 8 is the door open button to open the door.

FIG. 2 is a schematic cross-sectional view of the main part of the high-frequency heating device corresponding to FIG. 1. 9 is a high frequency oscillator that generates high frequency energy, and 10 is a waveguide for transmitting the high frequency energy from the high frequency oscillator 9 to the heating chamber 11. 12 is a turntable for uniform heating, on which the object to be heated is placed. In addition to the turntable 12, the uniform heating device includes a stirrer, a rotating antenna, a fixed antenna, etc., and any of them may be used. Reference numeral 13 denotes a transparent plate attached to the front surface of the door 2, and the transparent plate 13 is fixed to the door front plate 15 by a door cover 14.
A door rear plate 16 is attached to the door front plate 15 with screws 17. Door front plate 15 and door rear plate 1
6 are both made of metal plates, and form a radio wave attenuation cavity 19 facing the opening periphery 18 of the heating chamber 11. 20 is a transparent plate facing the heating chamber 11, and 21 is a wire mesh (or perforated metal plate). transparent plate 1
3. Heating chamber 1 through wire mesh 21 and transparent plate 20
You can see inside 1. 22 is a sash surrounding the door 2.

FIG. 3 is an enlarged sectional view of the vicinity of the radio wave attenuation cavity 19 shown in FIG. 2. Heating frequency for example 2450M
19a for the fundamental wave to prevent radio wave leakage to Hz and the second harmonic of the above frequency 4900M
One radio wave attenuation cavity 1 having one inlet 23 with second harmonic channel grooves 19b facing each other in opposite directions to prevent radio wave leakage for Hz.
9 is formed. In the fundamental wave channel groove 19a, the L-shaped radio wave propagation path (bold arrow) from the inlet 23 to the short-circuit surface 15a is approximately λ/4 with respect to the free space wavelength λ of the heating frequency. The fundamental wave chiyoke groove 19a is arranged on the side closer to the heating chamber 11, and one wall surface 16a of this groove 19a is used as a contact surface with the heating chamber opening periphery 18. In addition, in the second harmonic channel groove 19b, there is an L-shaped radio wave propagation path (thick line arrow) from the inlet 23 to the shorting surface 15b.
is approximately λ/8.

As described above, according to the present invention, as shown in FIG. 3, the fundamental wave channel groove and the second harmonic channel channel are opposed to each other in opposite directions, and the radio wave propagation path length in each channel groove is The required dimensions can be obtained by appropriately selecting the length in the direction parallel to the periphery of the opening of the heating chamber, and the door can be thin, so the thin electronic operation panel can be balanced. Therefore, it is possible to provide a high-frequency heating device that can be finished with a desirable appearance in terms of design.

[Brief explanation of the drawing]

FIG. 1 is an external view showing an embodiment of the high-frequency heating device of the present invention, FIG. 2 is a schematic sectional view of essential parts showing an embodiment of the high-frequency heating device of the present invention corresponding to FIG. 1, and FIG. 3 is an enlarged view of the vicinity of the radio wave attenuation cavity 19 in FIG. 2. FIG. 2...Door, 11...Heating chamber, 18...Heating chamber opening periphery, 19...Radio wave attenuation cavity, 19a...
Fundamental wave chiyoke groove, 19b... second harmonic chiyoke groove, 23... (radio wave attenuation cavity 19) entrance.

Claims (1)

[Claims] 1. A radio wave attenuation cavity 19 having one inlet 23 is provided on the periphery of the door 2 facing the heating chamber opening periphery 18, with the fundamental wave chiyoke groove 19a and the second harmonic chiyoke groove 19b facing in opposite directions. A high-frequency heating device characterized by the following configuration.