KR940008664B1 - Shelter constructure for electronic wave of microwave oven - Google Patents

Abstract

The radio wave shielding apparatus for excluding perfectly radio wave from a cavity of a microwave oven is disclosed, being easy in a choke cover installment with a graceful exterior view. The apparatus is constructed by a seal plate connected to a face of a front plate, a slit formed integrally with the seal plate, a damping groove formed by a folding part of the seal plate and a door flame joined to a front side of the seal plate and extended.

Description

Electromagnetic shielding device of microwave oven

1 is a perspective view of a conventional microwave oven.

2 is a cross-sectional view of a door of a conventional slit-mounted microwave oven.

3 is a sectional view of a door of a microwave oven in which the slits are integrally formed on a conventional seal plate.

4 is a slant perspective view of FIG.

5 is a slit perspective view of FIG.

6 is a door cross-sectional view of the microwave oven according to an embodiment of the present invention.

7 is a plan view of the slits according to the invention.

8 is a perspective view of the slits according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Front plate 2: Choke cover

3: door frame 4: seal plate

4 ': Integrated Slit 4 ": Integrated Slit

5: Mounting Slit

The present invention relates to a radio wave shielding device which can completely block radio waves leaking from a cavity of a microwave oven, has a beautiful appearance of a door, and is easy to assemble.

In the microwave shielding structure of the conventional microwave, as shown in FIG. 2, the mounting type slits 5 are installed in the door frame 3 to form a choke seal, and the seal plate 4 and the front plate ( 1) is made of double metal, and the choke cover (2) is installed between the door frame and the seal plate to shield the electromagnetic leakage.

That is, it is composed of double metal bonding, and the first choke seal and the second choke seal structure are formed in a complex manner. It was a structure to show.

3 is a form in which the slits 4 'are integrated with the seal plate 4, and the slits and choke seals have a structure of double metal bonding, and the slits 4' of the seal plate 4 have a tuning post. It attenuates electromagnetic waves primarily, and attenuates the secondary effect by the formation of choke seals. It is a triple structure that shields the radio waves by the double metal contact structure.

However, the apparatus of FIG. 2 has to form a space in the door frame 3 by installing the mounting type slits 5 in the door frame 3 so that the size of the door is increased, and the mounting type slits in the door frame 3 ( Failure to mount 5) in place had a problem of attenuation loss.

In addition, the apparatus of FIG. 3 has a lot of difficulties in mounting the choke cover 2 and is exposed to the outside when the door is opened.

An object of the present invention is to provide a radio wave shielding device that can completely block the radio waves leaking from the cavity of the micro-oven.

Seal plate is connected to the front plate surface in accordance with the object of the present invention in detail, a seal plate for attenuating the high frequency, the seal plate is formed integrally with the seal plate and is formed in multiple stages of the attenuation to attenuate the high frequency, Provided is a radio shielding device comprising a groove and a door frame connected to one surface of the bottom surface of the attenuation groove of the seal plate to form a second attenuation groove, the end of which is bent inwardly and connected to the front plate to attenuate high frequency. By the above configuration, it is possible to completely prevent the leakage of radio waves by blocking the radio waves leaking from the cavity in multiple stages.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

6 is a cross-sectional view of the radio wave shielding device according to the present invention, wherein the seal plate 4 and the integrated inlet 4 "positioned in the damping groove of the door frame 3 are In the slits, it consists of A and B, which are not cut parts, as shown in Figs. 7 to 8, and these are λ / 4 (1P = λ /) in which A + B is a constant period. Has 4).

And between one side of the door frame (3) and the seal plate (4) The shaped choke cover 2 is covered over the slits 4 "to form one or more attenuation grooves.

The seal plate is in contact with the front plate (1) to form a double metal, the end bending surface of the door frame (3) is also connected to the front plate to form a double metal.

The present invention configured as described above is as follows.

First, the seal plate 4 integral with the slit 4 " is bent so that the seal plate 4 surface is metal-to-metal contacted with the front plate 1 primarily. High frequency leakage is shielded, and a slitting (tuning post) having a certain period formed by TE mode (mode in which no electric field exists in the propagation direction of the radio wave) is installed so that the high frequency is attenuated secondarily. The choke seal is formed in to block leakage of high frequency in 3rd order.

In addition, a bending surface is formed on the surface of the door frame 3 to be qualitatively blocked by a capacitive seal structure in which the metal is in contact with the metal.

To explain this in more detail, radio waves leaking from the cavity into the gap between the front plate 1 and the door frame 3 are transmitted at the portion where the seal plate 4 and the front plate 1 are in contact with the double metal. After the shielding is attenuated, the remaining radio waves are distributed in the X and Z directions by the slits (4 ") and returned and attenuated in the (-) Y direction, and propagated by the primary choke seal structure composed of attenuation grooves. Is shielded in 3rd order.

In addition, in the process of distributing the radio waves in the X direction, the Z direction and the (-) Y direction, radio waves in the vector component direction, ie, the XY, YZ, and XZ directions, are generated. By shielding the secondary choke seal and the capacitive seal structure, the leakage of radio waves can be completely quadrupled.

Here,? / 4, which is a slit (4 ") period serving as a tuning post, is obtained by the TE mode. In the TEmn mode, the electric field distribution in the x and y directions is expressed as follows.

Equation 1

Equation 2

Where Kc ² = (mπ / a) ² + (nπ / b) ² ,

βg = K ² -Kc ² ,

K ² = ω ² εμ,

Hmn = any constant.

In addition,

Equation 3

Equation 4

Where m and n are the number of electric field calculations in the x and y directions, respectively, and λ is the wavelength in free space. Microwaves of any frequency must be λ <λg and λg> λ in order to be transmitted into a waveguide.

λ = 1 second propagation velocity / frequency = 122mm

λ / 4 = 122/4 = 30.5.

A in FIG. 7 or 8 serves as a tuning post, and its position is represented by Equations 1, 2, and 4

Equation 5

By deriving it, we establish at the point where the electric field is maximum in the direction of x. Differentiating Equation 5 can find the point where the electric field is maximum.

That is, where Ey '= 0 is where the electric field is maximum.

(N = 1, 3, 5 ..., 2m-1)

In other words, The in point is the point where the electric field is maximized, and an appropriate tuning post can be installed at this position to most effectively suppress wave transmission.

As described above, the present invention has an excellent leakage preventing shielding structure due to the quadruple blocking effect, thereby restricting microwaves coming from various directions, thereby increasing leakage preventing effect and providing a special structure without attaching the sleeve structure. It is easy to install and the appearance appears to have a beautiful effect.

Claims (1)

A seal plate 4 which forms a metal contact portion and attenuates high frequency while connecting to the front plate 1 surface, and a slitting which is formed integrally with the seal plate and formed in a multi-stage bending portion of the seal plate to attenuate high frequency ( 4 "), an attenuation groove formed by the bent portion of the seal plate, and a bonded end of the seal plate and extended to the back surface of the seal plate, and the inwardly bent end of the extension portion is connected to the front plate surface to attenuate the high frequency. Radio wave shielding device of the microwave oven, characterized in that consisting of a door frame (3) in association with the bent portion to form a second damping groove.