JPH0132317Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention improves the health of the human body by absorbing not only the fundamental wave but also the harmonics of microwaves leaking from a microwave heater to the outside. The present invention relates to a radio wave absorber that can prevent harmful effects on communication equipment and also prevent radio wave interference to communication equipment.

[Conventional technology]

Microwave heaters such as so-called microwave ovens and range ovens (hereinafter simply referred to as heaters).
has become widely popular due to its convenience. but,
Since these heaters use microwaves as their heating means, if leakage current occurs, it may have an adverse effect on human health or cause interference with communication equipment such as televisions and radio receivers. This has been recognized as a problem that needs to be solved.

Conventionally, in order to solve this leakage radio wave problem, a radio wave absorbing material is formed by incorporating ferrite, which has the ability to absorb radio waves of about 2.45 GHz, which is the fundamental wave of the heater, into a synthetic resin. As shown in FIG. 4, the radio wave absorbing material is formed into a frame shape to constitute a radio wave absorber a, which is attached to the front surface of the heater body b or the inner surface of the door c.

[Problem that the invention attempts to solve]

In conventional radio wave absorbers, the type of ferrite and synthetic resin and the content ratio of ferrite are set so that its absorption capacity is maximum for the fundamental wave of the heater, but it is difficult to absorb the microwaves leaking from the heater. Although its power is relatively small compared to the fundamental wave, there are harmonics that are integral multiples of the fundamental wave, subharmonics that are reciprocal multiples of the fundamental wave, and other noise accompanying the fundamental wave. The effects these have on televisions, radio receivers, etc. are serious. Conventional radio wave absorbers did not have any preventive measures against microwaves with frequencies other than these fundamental waves, so there is no way to prevent radio wave interference to communication equipment caused by leaked radio waves other than these fundamental waves. I stopped talking.

By the way, as a technique aimed at preventing leakage of harmonics, there is a technique disclosed in, for example, Japanese Patent Application Laid-open No. 1096/1983. This is between the open end of the front of the microwave heater and the inside of the door.
A plurality of composite ferrites with different resonance frequencies are laminated in the thickness direction of the gap between the main body and the door. However, this technology is not intended to prevent fundamental wave leakage, and
Because each layer is laminated in the thickness direction of the gap, even if a fundamental wave absorption layer is formed in a specific layer of each layer, the fundamental wave absorption layer only exhibits the ability to absorb the fundamental wave. , harmonics will pass through the fundamental wave absorption layer without attenuation, and for harmonics this is essentially equivalent to widening the gap, so strict control of the gap between the main body and the door is required. There were problems with the technology applied to microwave heaters.

[Means for solving problems]

The present invention was developed in view of the current situation, and its gist is that in a radio wave absorbing device that is attached to the front of the heater body or the inside of the door, the outer edge side has a radio wave absorber that absorbs radio waves for the fundamental wave of the heater. A fundamental wave absorbing part made of a synthetic resin containing ferrite having the ability to absorb radio waves is placed, and a synthetic resin containing ferrite having the ability to absorb radio waves for harmonics of the fundamental wave is placed on the inner edge side to prevent leakage. The present invention is characterized in that the harmonic absorbing portion formed by containing the above components is positioned and integrally molded with each other to constitute a leakage radio wave absorber in a microwave heater.

[Effect]

If the radio wave absorber constructed in this manner is attached to a predetermined position of the heater and the heater is used, the fundamental wave component of the microwaves passing through the front surface of the heater body and the inner surface of the door will be absorbed by the fundamental wave absorber. Furthermore, the harmonic components are absorbed by the harmonic absorber and are attenuated, so the fundamental wave, which has a relatively strong electromagnetic field strength and has a negative effect on human health, can also be used as a radio wave that is harmful to communication equipment. Harmonic waves that cause interference can also be absorbed, and most of the various harmful effects caused by leakage radio waves can be eliminated.

In the present invention, the harmonic absorption section is arranged on the inner edge side and the fundamental wave absorption section is arranged on the outer edge side, so even when the microwave passes straight through the gap between the heater body and the inner surface of the door, Furthermore, even when the light passes through the gap while being reflected, the light first enters the harmonic absorption section and then enters the fundamental wave absorption section. Since the harmonic absorber has a slight ability to absorb the fundamental wave, the fundamental wave is attenuated to a certain extent by the harmonic absorber, and then enters the fundamental wave absorber and is significantly attenuated. In this way, leakage of the fundamental wave is prevented through a two-step attenuation process, so the chance of the fundamental wave absorbing part melting due to induction heating by microwaves is drastically reduced, and the boundary between the high frequency absorbing part and the fundamental wave absorbing part is Even if a melting phenomenon were to occur in the vicinity, the melted synthetic resin would not flow out to the outside because the harmonic absorption section is adjacent to the melted portion. In addition, the fundamental wave absorbing section and the harmonic absorbing section are provided in parallel in a direction perpendicular to the thickness of the gap between the heater body and the inner surface of the door, so unlike the conventional laminated structure leakage radio wave absorber, the gap will not actually expand.

〔Example〕

Next, details of the present invention will be explained based on illustrated embodiments.

Fig. 1 is a perspective view showing an embodiment of the leakage radio wave absorber in a heater according to the present invention, Fig. 2 is an enlarged cross-sectional view of the main part of the leakage radio wave absorber, and Fig. 3 is an enlarged sectional view of the leakage radio wave absorber. FIG. 3 is a perspective view showing how it is attached to the heater.

The leakage radio wave absorber 4 is connected to the heater body 1 and the door 2.
In order to absorb the microwaves passing through the gap 5 between
Opening front end surface 3 or inner surface 8 of the door on the front side of the heater main body 1
In the illustrated example, the door is attached to the front end surface 3 of the opening, but the attachment location may also be the inner surface 8 of the door. The leakage radio wave absorber 4 has a frame shape corresponding to the shape of the front end surface 3 of the opening, and on its outer edge side, ferrite having radio wave absorption ability for the fundamental wave of the heater, for example 2.45 GHz, is appropriately synthesized. A fundamental wave absorbing portion 6 formed by incorporating resin is located, and the other inner edge side has a radio wave absorbing ability for harmonics that cause radio wave interference to televisions and radio receivers among the harmonics of the fundamental wave. A harmonic absorbing portion 7 formed by incorporating ferrite in a suitable synthetic resin is positioned therein.

As the ferrite used in the harmonic absorption section 7, it is preferable to select one or more types from among nickel zinc ferrite, barium ferrite, manganese ferrite, magnesium zinc ferrite, etc.; Other ferrites may be used as long as they have a resonance frequency that substantially matches harmonics. In addition, the synthetic resin materials used for the fundamental wave absorption section 6 and the harmonic absorption section 7 include polypropylene,
It is possible to select one or more types from among polyamide, polyphenylene sulfide, vinyl chloride, etc., but when making a specific selection, it is possible to select the internal temperature of various heaters such as microwave ovens and range ovens. It is necessary to consider one of the conditions that it does not melt.

The fundamental wave absorbing part 6 and the harmonic absorbing part 7 made of such materials are integrally molded by multi-color molding, but at this time, when the molding is done and cured, the frame-shaped radio wave absorbing device 4 is bonded to the outer edge side member and the inner part. In order to prevent bending due to the difference in thermal expansion coefficient with the edge member and distortion,
It goes without saying that it is preferable to use the same synthetic resin for the fundamental wave absorbing section 6 and the harmonic absorbing section 7, and to use resins with similar specific gravity of ferrite contained in both. Also, the harmonic absorption section 7
As a result of experiments, it has been found that the content ratio of ferrite to synthetic resin is within the range of 0.25 to 9.0% by weight of ferrite to 1 part synthetic resin, which has sufficient absorption ability for harmonics. It was done.

In the illustrated example, the radio wave absorber 4 is formed into a frame shape in order to simplify the assembly process and facilitate handling. However, by forming each side separately and attaching it to the heater, Of course, it is also possible to have a configuration in which the heater is assembled into a shape, and other suitable methods such as fitting, welding, or using an appropriate attachment member may be employed for attachment to the heater. Further, in this embodiment, the harmonic absorbing section 7 located on the inner edge side of the radio wave absorbing device 4 has only one layer, but for example, the frequency band of harmonics to be absorbed is wide, and it cannot be covered by just one layer of harmonic absorbing section. If this is not possible, it may be considered as an application example to provide a plurality of layers of harmonic absorbing portions having the ability to absorb the target harmonics. In addition, the concept of the leakage radio wave absorber according to the present invention is effective not only for preventing leakage of harmonics but also of subharmonics. It is sufficient to select a ferrite that approximately matches the .

Therefore, if the heater equipped with the leakage radio wave absorber according to the present invention is used, the fundamental wave component of the microwave passing through the gap 5 between the heater body 1 and the door 2 will be absorbed by the fundamental wave absorber 6. Furthermore, the harmonic components are absorbed and attenuated by the harmonic absorber 7, which prevents harmonics from leaking to the outside of the heater, not only the fundamental waves that are harmful to the body, but also the harmonics that cause trouble to television and radio receivers. can also be effectively prevented. In addition, since the harmonic absorbing section 7 on the inner edge side has a slight absorption ability for the fundamental wave, the fundamental wave after passing through the harmonic absorbing section 7 is attenuated and becomes the fundamental wave. The electromagnetic field strength of the microwaves incident on the absorption unit 6 is the same as the electromagnetic field strength of the microwaves incident on the radio wave absorber when a conventional radio wave absorber having radio wave absorption ability only for the fundamental wave is arranged. Since it can be made smaller in comparison, it is also possible to avoid partial melting of the radio wave absorber due to induction heating, which conventionally tends to occur due to excessive incidence of microwaves.

[Effect of idea]

A leakage radio wave absorber for a microwave heater according to the present invention includes a fundamental wave absorbing part having a radio wave absorbing ability for the fundamental wave of the heater and a harmonic absorbing part having a radio wave absorbing ability for harmonics of the fundamental wave. and at the same time,
Since this is installed on the front of the heater body or on the inside of the door, the electromagnetic field strength of the microwaves leaking from the gap between the heater body and the door is relatively strong, which is harmful to human health. The waves too
In addition, harmonics that cause radio wave interference in televisions, radio receivers, etc. are also absorbed, making it possible to remove most of the harmful microwaves leaking from microwave heaters. This allows work to be carried out near the microwave heater with peace of mind, and allows the installation of televisions and radio receivers to be done freely without having to consider the positional relationship with the microwave heater.

The leakage radio wave absorber of the present invention has a harmonic absorber located on the inner edge side and a fundamental wave absorber located on the outer edge side, so the microwaves passing through the gap between the heater body and the door are , whether the light passes straight through the gap or passes while being reflected, it first enters the harmonic absorption section and then enters the fundamental wave absorption section. Since the harmonic absorption section has some absorption ability for the fundamental wave,
The fundamental wave that has passed through the harmonic absorption section is attenuated to a certain extent, and then enters the fundamental wave absorption section where it is significantly attenuated. Since the fundamental wave with such a large power is attenuated through a two-step attenuation process, it is difficult to make the fundamental wave on the inner edge side of the fundamental wave absorber, as in the conventional case where it is suddenly introduced into the fundamental wave absorber with high attenuation performance. Not only does this dramatically reduce the chance of the synthetic resin melting due to microwave induction heating, but even if melting occurs, the harmonic absorption area is adjacent to the melted area, so the molten synthetic resin will not flow out. There is no such thing. In addition, since the fundamental wave absorbing section and the harmonic absorbing section are arranged in parallel in the direction perpendicular to the thickness direction of the gap between the heater body and the inner surface of the door, they are similar to conventional leakage wave absorbers laminated in the thickness direction. , the gap does not substantially widen. Furthermore, some microwave heaters are equipped with a chiyoke groove, one end of which is opened on the inner edge of the open end of the front of the heater body, in order to prevent leakage of fundamental waves from between the heater body and the door. However, when this leakage radio wave absorber is used in such a microwave heater, the harmonic absorber closes the opening of the chiyoke groove.
It becomes possible to prevent dirt and the like from entering the chiyoke groove. Moreover, since it is the harmonic absorbing part that closes the opening of the chiyoke groove, the fundamental wave that passes through this part is attenuated slightly, but most of it passes through, so the function of the chiyoke groove is fully utilized. be. In addition, since the leakage radio wave absorber according to the present invention has a fundamental wave absorbing part and a harmonic absorbing part integrally molded, manufacturing costs can be reduced and handling is easy, and it can be applied to all kinds of microwave heaters. It is.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of the leakage radio wave absorber in a heater according to the present invention, Fig. 2 is an enlarged cross-sectional view of the main part of the leakage radio wave absorber, and Fig. 3 is an enlarged sectional view of the leakage radio wave absorber. FIG. 4 is a perspective view showing how a conventional leakage wave absorber is attached to a heater. 1: Heater body, 2: Door, 3: Opening front end surface, 4: Radio wave absorber, 5: Gap, 6: Fundamental wave absorber, 7: Harmonic absorber, 8: Door inner surface, a: Radio wave absorber , b: heater body, c: door.

Claims (1)

[Claims for Utility Model Registration] 1. In a radio wave absorber that is attached to the front of the main body of a microwave heater or the inner surface of the door, the outer edge side is composed of ferrite that has the ability to absorb radio waves for the fundamental wave of the microwave heater. A fundamental wave absorbing portion formed by containing it in a resin is located, and on the inner edge side, a synthetic resin containing ferrite having a radio wave absorption ability for harmonics of the fundamental wave to prevent leakage is formed. A leakage radio wave absorber in a microwave heater in which harmonic absorbers are positioned and integrally molded together. 2. The microorganism according to claim 1 of the utility model registration claim, wherein one or more types of ferrite are selected from among nickel zinc ferrite, barium ferrite, manganese zinc ferrite, and magnesium zinc ferrite as the ferrite contained in the harmonic absorption part. A leakage radio wave absorber in a wave heater. 3. Claims No. 3 for Utility Model Registration in which one or more of polypropylene, polyamide, polyphenylene sulfide, vinyl chloride, etc. are selected as the synthetic resin material of the fundamental wave absorbing portion and the harmonic absorbing portion. A leakage radio wave absorber in the microwave heater according to item 1 or 2. 4. A leakage radio wave absorber in a microwave heater as set forth in claim 1, 2, or 3 of the utility model registration claim, wherein the same synthetic resin is used for the fundamental wave absorbing portion and the harmonic absorbing portion. 5. Claim 1 of the above-mentioned utility model registration, in which the specific gravity of the ferrite contained in the fundamental wave absorption part and the ferrite contained in the harmonic absorption part are approximated.
A leakage radio wave absorber in a microwave heater according to item 1, 2, 3, or 4. 6 Claims 1 and 2 of the above-mentioned utility model registration claims, in which the blending ratio of synthetic resin and ferrite in the harmonic absorption part is set within the range of 0.25 to 9.0 by weight of ferrite to 1 part of synthetic resin. , a leakage radio wave absorber in a microwave heater according to item 3, item 4, or item 5.