JPH0110879Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(a) Industrial application field The present invention relates to a microwave oven. (b) Conventional technology In order to reduce the temperature rise inside the microwave oven,
A ventilation section consisting of a group of slits is provided in the metal exterior cabinet (see, for example, Japanese Utility Model Publication No. 59-6171). Radio wave leakage from such ventilation parts is weak,
Until now, this has not been a problem, but since the harmonics of the radio waves used in microwave ovens fall into the reception band of satellite broadcasting, which has recently been started, it is necessary to further improve the prevention of radio wave leakage from such ventilation parts. requested. (c) Problems that the invention aims to solve If the opening of the slit that constitutes the ventilation section is made smaller, the leakage of radio waves from the ventilation section will be reduced, but
In this case, the ventilation effect of the ventilation section is also reduced, which is not preferable. (d) Means for solving the problem Conventionally, the longitudinal direction of each slit in the group of slits constituting the ventilation section was all in the same direction, but in the present invention, the longitudinal direction of the slit group constituting the ventilation section is in the same direction. It is configured by providing a plurality of parallel slit groups consisting of shaped slits, and in the plurality of parallel slit groups,
It is characterized in that opposing sides of adjacent groups of parallel slits are parallel to each other and the longitudinal directions of the slits of adjacent groups of parallel slits are different from each other. (E) Effect The radio waves that are about to leak from the ventilation section have various planes of polarization, and therefore, a plurality of groups of parallel slits in which the longitudinal directions of the slits in adjacent groups are different from each other prevents leakage of radio waves with various planes of polarization. Has a mitigating effect. Since radio waves can be viewed as a combination of two orthogonal polarization planes, a plurality of parallel slit groups in which the longitudinal directions of the slits in each group are orthogonal to each other are particularly preferred. (F) Embodiment Figure 1 shows the back side of a microwave oven according to an embodiment of the present invention. A metal exterior cabinet 1 encloses a heating chamber 2 and an electrical compartment 3 adjacent thereto. The electrical equipment room 3 accommodates electrical parts such as magnetrons, and a ventilation section 4 is provided on the back wall 1a of the exterior cabinet, which also serves as the wall of the electrical equipment room 3. The ventilation section 4 includes a first parallel slit group 4a consisting of three linear slits 5 whose longitudinal directions are parallel to each other and vertical, and three linear slits whose longitudinal directions are parallel to each other and horizontal. 5
The second parallel slit groups 4b each consist of three groups arranged in a staggered manner. In addition, these parallel slit groups 4a and 4b are arranged such that the opposing sides of the adjacent parallel slit groups are parallel and close to each other and face each other. That is, for example, the right side 6 of the first parallel slit group 4a ₁ on the left side of _the lower stage in FIG. The upper side 8 of the second parallel slit group 4b ₁ is parallel to and faces the lower side 9 of the first parallel slit group 4a ₂ on the right side of the middle stage located immediately above it. The table below shows the measurement results of radio wave leakage from the ventilation section 4. In this measurement, a horn antenna was installed at a position 3 m behind the back wall 1a of the exterior cabinet, and the horizontal polarization intensity and vertical polarization intensity of the leaked radio waves were measured. All the slits 5 in the figure are arranged horizontally (FIG. 4) and vertically (FIG. 3), and the conditions are the same as in FIG. 1.

[Table] As shown in the table above, in Reference Examples A and B, the radio wave leakage intensity of vertically polarized waves and horizontally polarized waves is large, respectively, whereas in the example, the radio wave leakage intensity is large for either vertically or horizontally polarized waves as in the reference example. On the other hand, there is no protruding leakage,
The radio wave leakage intensity on both planes of polarization can be equally reduced. Moreover, in the example, the opposing sides of the adjacent groups of parallel slits are close to each other in parallel and face each other, and the aperture ratio of the slits is not much different from that in the reference examples A and B, which may reduce the amount of ventilation. do not have. (g) Effects of the invention According to the invention, in a microwave oven in which a ventilation section consisting of a group of parallel slits is provided in a metal exterior cabinet, it is possible to further reduce radio wave leakage from the ventilation section without impairing the ventilation effect. .

[Brief explanation of drawings]

FIG. 1 is a rear perspective view of a microwave oven according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main parts thereof, and FIGS. 3 and 4 are front views of main parts of a reference example. 1... Exterior cabinet, 4... Ventilation section, 4
a, 4b...first and second parallel slit groups.

Claims (1)

[Scope of claims for utility model registration] (1) A ventilation section provided in a metal exterior cabinet,
A plurality of parallel slit groups each consisting of a plurality of parallel linear slits are provided, and in the plurality of parallel slit groups, opposing sides of adjacent parallel slit groups are made parallel to each other and adjacent parallel slit groups are arranged in parallel. A microwave oven characterized in that the longitudinal directions of the slits are different from each other. (2) The microwave oven according to claim 1 of the utility model registration, characterized in that the longitudinal directions of the slits of the adjacent groups of parallel slits are orthogonal to each other.