KR20060010198A - Micro wave interception apparatus of microwave oven - Google Patents

Abstract

The electromagnetic shielding device of the electromagnetic heater of the present invention forms an electromagnetic leakage blocking choke capable of primarily blocking the leakage of electromagnetic waves on the inner edge of the door, and is not blocked by the electromagnetic leakage blocking choke on the outside of the electromagnetic leakage blocking choke. An electromagnetic wave blocking filter is formed to secondarily block the remaining leakage electromagnetic waves so that electromagnetic waves leaking between the front wall of the main body and the inner surface of the door are blocked first by the electromagnetic leakage blocking choke and secondly by the electromagnetic leakage blocking filter. By doing so, leakage of electromagnetic waves can be reliably cut off.

Description

Electromagnetic shielding device of electromagnetic wave heater {MICRO WAVE INTERCEPTION APPARATUS OF MICROWAVE OVEN}

1 is a perspective view of a conventional microwave oven.

Figure 2 is a cross-sectional view showing an example of a conventional electromagnetic shielding filter.

Figure 3 is a graph showing the conventional electromagnetic wave attenuation characteristics.

4 is a perspective view of a microwave oven equipped with an electromagnetic shield according to the present invention.

5 is a partially cutaway perspective view of FIG. 4.

Figure 6 is a longitudinal sectional view showing an electromagnetic wave shield of the present invention.

7 is a modification of the electromagnetic leakage blocking choke according to the present invention.

8 is a modification of the electromagnetic leakage cutoff filter according to the present invention.

9 is a graph showing the shielding characteristics of the present invention.

Explanation of symbols on the main parts of the drawings

101: body 101a: front wall

102: cavity 103: door

103a: inner side 120: electromagnetic leakage blocking choke

130: electromagnetic leakage blocking filter 130a: vertical portion

130b: first bent part 130c: second bent part

131: slot

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electromagnetic wave shielding devices for electromagnetic wave heaters such as microwave ovens or electric ovens, and more particularly, to electromagnetic wave shielding devices for electromagnetic wave heaters having a sufficient shielding bandwidth even in a gap between doors.

In the conventional microwave oven, as shown in FIG. 1, the door 2 is opened and closed so as to open and close an opening on a front surface of the main body 1 having a front surface open as a rectangular box body. The main body 1 is provided with a magnetron (not shown) for generating electromagnetic waves supplied into the main body 1.

In addition, the main body 1 has a cavity 3 so that the front surface is opened and a predetermined space for accommodating food therein, and the cavity 3 can be a resonance space for heating food in the state in which the door 2 is closed. It is provided, and the electromagnetic shielding filter (4) is formed on the inner surface of the door (2) to form a magnetic field to shield the leakage of electromagnetic waves.

The electromagnetic shielding filter 4 has a first bent portion 4b and a second bent portion 4c continuously bent at 90 degrees to a vertical portion 4a formed in the width direction at the edge of the door 2, so that the microphone The end of the second bent portion (4c) to form a predetermined interval (d) at the end of the door 2, a predetermined width along the first bent portion (4b) and the second bent portion (4c) Slots 6 are formed periodically.

That is, the gap G: gap between the wall front surface 1a of the main body 1 and the second bent portion 4c becomes the capacitance C: the second bent portion 4c and the vertical portion 4a. ) Is a series LC circuit with inductance (L: inductance).

Electromagnetic waves resonating in the cavity 3 of the microwave oven by the electromagnetic shielding filter 4 constituting the series LC circuit as described above are introduced into the gap G between the front wall 1a of the main body 1 and the door 2. Leakage is blocked.

However, the conventional electromagnetic shielding filter 4 has a large performance difference according to the size of the gap G, and the degree of blocking of electromagnetic leakage according to the size of the gap G is shown in the graph of FIG. 3. .

The graphs measure the degree of electromagnetic leakage when the gap G is 1 mm, 3 mm, and 10 mm, respectively, and as the gap G opens, the breaking performance decreases rapidly. When designing a microwave oven, it is usually designed to operate near the area where electromagnetic leakage is blocked to the maximum, so the wider the bandwidth of this part, the better, and the performance can be estimated with the bandwidth of -60dB or less. As can be seen in the graph of FIG. 3, when the width of the band is wider than about 300 MHz at 1 mm, the gap G is widened, and the bandwidth is narrowed sharply, and at 10 mm, the band width is reduced to about 10 MHz, so that the shielding performance is rapidly reduced. .

That is, in the conventional microwave oven, although the electromagnetic wave shielding filter 4 for blocking the leakage of electromagnetic waves is provided, the shielding performance has a problem that the shielding performance is sharply lowered if the gap G occurs to a certain degree.

The object of the present invention devised in view of the above problems is to provide an electromagnetic wave shielding device of an electromagnetic heater suitable for sufficiently shielding the leakage of electromagnetic waves with a wide bandwidth even if there is some gap between the wall of the main body and the door. In providing.

In order to achieve the object of the present invention as described above

A cavity is formed inside the main body made of a box body, and a door is provided in the front opening of the cavity so as to be openable and openable. The main body is provided with electromagnetic waves for heating the dielectric material. In the electromagnetic heater provided with a magnetron for generating internally,

On the inner side of the door, an edge of the electromagnetic leakage primary blocking mechanism is formed at the edge to primarily block the leakage of electromagnetic waves of the cavity to the outside through a gap between the front wall of the main body and the inner surface of the door,

Electromagnetic shielding of the electromagnetic wave heater, characterized in that the electromagnetic leakage secondary cut-off mechanism is formed outside the electromagnetic leakage primary cut-off mechanism to secondly block electromagnetic waves leaking into the gap without being blocked by the electromagnetic leakage primary cut-off mechanism. An apparatus is provided.

Hereinafter, with reference to the embodiment of the accompanying drawings, the electromagnetic wave shielding device of the electromagnetic wave heater of the present invention configured as described above in detail as follows.

Figure 4 is a perspective view of a microwave oven equipped with an electromagnetic shield according to the present invention, Figure 5 is a partially cutaway perspective view of Figure 4, Figure 6 is a longitudinal sectional view showing the electromagnetic shield of the present invention.

As shown in the drawing, in the microwave oven provided with the present invention, a cavity 102 for storing food is formed inside the main body 101 of a box body, and the door 103 is formed at the front opening of the cavity 102. Is opened and closed to open and close, the main body 101 is provided with a magnetron (not shown) for generating an electromagnetic wave to the cavity 102.

On the inner side surface of the door 103, electromagnetic waves of the cavity 102 are directed to the outside through a gap G between the wall front surface 101 a of the main body 101 and the inner side surface 103 a of the door 103. Electromagnetic shielding device 110 is provided to block leakage.

The electromagnetic shielding device 110 has a cavity 102 at the inner edge of the door 103 through a gap G between the front surface 101a of the main body 101 and the inner surface 103a of the door 103. The electromagnetic leakage blocking choke 120 is formed to primarily block the leakage of electromagnetic waves to the outside, and is not blocked by the electromagnetic leakage blocking choke 120 outside the electromagnetic leakage blocking choke 120. An electromagnetic wave blocking filter 130 is formed to secondarily block electromagnetic waves leaking into the gap G.

The electromagnetic leakage blocking choke 120 is formed to be concave in the form of a diverge (c) of a predetermined depth and to form a closed loop shape, and the depth (D) is formed to be around λ / 4.

7 shows modified examples of the electromagnetic leakage blocking choke 120, in which a protrusion 120a is formed below the inlet portion as shown in a), or b) inwardly bent inward at an end portion of the protrusion 120a as shown in FIG. Various forms are possible, such as the form in which the bent part 120b is formed, and the form in which the protrusion part 120a is formed in the upper and lower sides of the inlet part as in c).

The electromagnetic wave filter 130 has a first bent portion 130b and a second bent portion 130c continuously bent at 90 degrees to a vertical portion 130a formed at the edge of the door 103 in the width direction, so that a microphone Form, the end of the second bent portion (130c) to form a predetermined interval (d) at the end of the door 103, and periodically along the first bent portion (130b) and the second bent portion (130c) Slot 131 is formed periodically to form an electrically series LC circuit.

FIG. 8 illustrates modified examples of the electromagnetic wave filter 130, and as shown in FIG. 8A, a third bent portion 130d is bent again into the second bent portion 130c or b). As described above, various forms such as a form in which the protrusion 130e protruding upward is formed at the lower side of the inlet.

As described above, the microwave oven of the present invention configured to block the leakage of electromagnetic waves in a double way has a gap between the front surface 101a of the main body 101 and the inner surface 103a of the door 103 of the cavity 102. When leaking to G), the electromagnetic wave leaking out of the primary phase is canceled by the electromagnetic wave having a reversed phase reflected from the electromagnetic leakage blocking choke 120 formed so that the depth D is recessed to λ / 4.

As described above, some electromagnetic waves may leak even when the leakage of the electromagnetic waves is primarily blocked in the electromagnetic leakage blocking choke 120. The electromagnetic waves leaked in this way may be bent at the front surface 101a of the main body 101 and the second bend. An electric series LC circuit in which the gap G of the portion 130c becomes a capacitance (C: capacitance), and an inductance (L: inductance) is formed between the second bend portion 130c and the vertical portion 130a. Electromagnetic waves are reflected from the electromagnetic wave blocking filter 130 forming a leakage.

9 is a graph showing the shielding property of the present invention, as shown in the graph, when the gap G between the front surface 101a of the main body 101 and the inner surface 103a of the door 103 is 10 mm. Edo -60dB 'bandwidth is very wide, such as 150 MHz, showing good shielding performance.

As described above in detail, the electromagnetic wave shielding device of the electromagnetic heater of the present invention forms an electromagnetic leakage blocking choke capable of primarily blocking the leakage of electromagnetic waves at the inner edge of the door, and electromagnetic waves outside the electromagnetic leakage blocking choke. An electromagnetic wave blocking filter is formed to secondaryly block the remaining leakage electromagnetic waves that are not blocked by the leakage blocking choke, and electromagnetic waves leaking between the front wall of the main body and the inner surface of the door are blocked by the electromagnetic leakage blocking choke and the electromagnetic leakage blocking filter twice. By doing so, it is possible to reliably block leakage of electromagnetic waves.

Claims (3)

A cavity is formed inside the main body made of a box body, and a door is provided in the front opening of the cavity so as to be openable and openable. The main body is provided with electromagnetic waves for heating the dielectric material. In the electromagnetic heater provided with a magnetron for generating internally, On the inner side of the door, an edge of the electromagnetic leakage primary blocking mechanism is formed at the edge to primarily block the leakage of electromagnetic waves of the cavity to the outside through a gap between the front wall of the main body and the inner surface of the door, Electromagnetic shielding of the electromagnetic wave heater, characterized in that the electromagnetic leakage secondary cut-off mechanism is formed outside the electromagnetic leakage primary cut-off mechanism to secondly block electromagnetic waves leaking into the gap without being blocked by the electromagnetic leakage primary cut-off mechanism. Device. The method of claim 1, The electromagnetic leakage primary blocking mechanism The inner surface of the door is formed to be recessed in a predetermined depth (C) and to form a closed loop shape, and the depth (D) is an electromagnetic leakage blocking choke formed to be around λ / 4. Electromagnetic shielding device of the electromagnetic heater. The method of claim 1, The electromagnetic leakage secondary blocking mechanism The first bent portion and the second bent portion are continuously bent at 90 degrees to a vertical portion formed in the width direction at the edge of the door to form a meso (ㅁ), and the end of the second bent portion has a predetermined distance d from the end of the door. The electromagnetic wave shielding device of the electromagnetic wave heater of claim 1, wherein the slots are periodically formed along the first bent portion and the second bent portion to form an electrically series LC circuit.

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