KR100575687B1 - Microwave 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, the leakage of electromagnetic waves is reliably cut off, and since the slot is not exposed to the outside, a separate structure for covering the slot is unnecessary.

Description

Electromagnetic shielding device of electromagnetic wave heater {MICROWAVE 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 the door 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 of the present invention.

8 is a modification of the electromagnetic wave filter of 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

The present invention relates to an electromagnetic wave shielding device of an electromagnetic heater such as a microwave oven or an electric oven, and in particular, the electromagnetic shielding device of the electromagnetic wave heater that has a sufficient shielding bandwidth and can eliminate unnecessary structures even when the gap of the door is somewhat open. It is about.

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).

As described above, the electromagnetic wave resonated in the cavity 3 of the microwave oven by the electromagnetic shielding filter 4 constituting the series LC circuit has a gap between the front surface 1a of the wall 1a of the main body 1 and the door 2. Leakage to G) 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.

In addition, since the slot 6 is formed in the first bent portion 4b exposed to the outside of the electromagnetic shielding filter 4, there is a problem that a separate structure for covering the slot 6 portion is required.

The object of the present invention devised in view of the above problems is to allow sufficient shielding of the leakage of electromagnetic waves with a wide bandwidth even if there is a gap between the wall of the main body and the door, and to eliminate unnecessary structures. To provide an electromagnetic shield of the electromagnetic heater suitable for the purpose.

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. The device 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.

4 is a perspective view of a microwave oven equipped with an electromagnetic shield according to the present invention, FIG. 5 is a partially cutaway perspective view of the door of FIG. 4, and FIG. 6 is a longitudinal sectional view showing the electromagnetic shielding device 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 width 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 The end of the second bent portion 130c forms a predetermined interval d at the end of the door 103, and the slot 131 is periodically spaced at the second bent portion 130c at regular intervals. Formed to form an electrically series LC circuit.

The slot 131 is press-processed in a rectangular shape so as to be open at an end of the second bent portion 130c.

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 manner 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, the leakage of electromagnetic waves can be reliably cut off.

In addition, since the slot of the electromagnetic leakage blocking filter is formed in the second bent portion, since the slot is not exposed to the outside, there is an effect that can exclude the separate structure to cover the side slot.

Claims (2)

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, The inner surface of the door is formed to be recessed in a definite shape (C) of a predetermined depth and to form a closed loop shape, and the depth (D) of the electromagnetic wave leakage blocking choke and its electromagnetic wave are formed to be around λ / 4. The first bent portion and the second bent portion are continuously bent at 90 degrees in a vertical portion formed on the outside of the leakage blocking choke in the width direction of the door to form a meso shape, and the end of the second bent portion is predetermined at the end of the door. The electromagnetic wave shielding device of the electromagnetic wave heater, characterized in that to achieve the interval (d), and the slot is formed in the second bent portion periodically to form a double shielding structure consisting of the electromagnetic leakage blocking filter to form an electrically series LC circuit. . The method of claim 1, The slot is electromagnetic shielding apparatus of the electromagnetic heater, characterized in that the end is processed to be removed in a rectangular form to open.

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