JP2023147405A - microwave shielding device - Google Patents

Abstract

To provide a microwave shielding device having high shielding performance so that microwaves to be radiated to food that is not desired to be heated (i.e., a processing target object to which microwaves are not desired to be radiated) can be shielded with as a simple configuration as possible.SOLUTION: A patch (a second conductive member having a narrow area) 22 on a reflection-phase small side is arranged so as to face at least a part of a processing target object (a part that is not desired to be processed) 10, whereby for a processing target object at a position the reflection-phase small side faces, "antinodes" where electric fields of standing waves strengthen each other are less likely to occur, and "nodes" where the electric fields weaken each other are more likely to occur. As a result, it becomes difficult for microwaves to concentrate on at least a part (a portion which is not desired to be processed) 10 of the processing target object. In other words, shielding performance for shielding microwaves can be improved as compared with the prior art, and it is possible to restrain progress of the processing of parts which are not desired to be processed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a microwave shielding device that blocks irradiation of microwaves to at least a portion of a workpiece when the workpiece is irradiated with microwaves for treatment.

A microwave oven, which is a typical microwave processing device, dielectrically heats food, which is a typical object to be processed, placed inside the processing chamber by irradiating microwaves into the processing chamber. At this time, the processing chamber is covered with a metal wall to prevent microwaves from leaking outside, and the microwaves are repeatedly reflected within the processing chamber, irradiating and heating every part of the food. In particular, it is known that standing waves, that is, "bellies" where electric fields strengthen each other and "nodes" where electric fields weaken each other, occur, and food located in the "bellies" is more likely to be heated.

However, there are many different types of food, and it is not always desirable to heat them all. For example, in a Makunouchi bento, you want to heat the rice and side dishes, but you don't want to heat the raw vegetables, pickles, vinegared foods, or fruits. Therefore, for example, Patent Document 1 discloses a method for preventing irradiation of microwaves to foods that are not desired to be heated. Patent Document 1 shows an example in which a container for storing food that is not desired to be heated has a material layer that reflects or absorbs microwaves on the inside of the container. The reflective material is a coating film or metal-deposited film containing conductive particles selected from carbon black, copper, aluminum, silver, nickel, cobalt, and titanium for heat-resistant resins including epoxy resins and polyester resins. is shown, and ferrite is shown as the absorbing substance.

JP 2019-135157 Publication

However, the conventional microwave processing equipment has insufficient microwave shielding performance, so it requires both a recess and a lid for the container that contains the food that you do not want to heat, and a material layer that reflects or absorbs the entire surrounding area. If you don't surround it, you won't get a sufficient shielding effect. Therefore, in the end, it is necessary to use a special container with a specific enclosed shape, and to mold the food that you do not want to heat to fit the shape of the container, which reduces the flexibility of portion size and presentation. The problem was that it was severely damaged.

The present invention solves the above-mentioned conventional problems, and is designed to shield microwaves irradiated to foods that do not want to be heated (i.e., objects to be treated that do not want to be irradiated with microwaves) with a simple configuration as possible. The purpose is to provide a microwave shielding device with high shielding performance.

In order to solve the above-mentioned conventional problems, the microwave shielding device of the present invention is arranged in the processing chamber in a microwave processing device that processes an object to be processed in the processing chamber by irradiating microwaves, and the microwave shielding device of the present invention The smaller side is arranged to face at least a portion of the object to be processed.

Here, we discovered that on the side of the microwave shielding device where the reflection phase is small, ``antinodes'' where the electric fields of standing waves strengthen each other are less likely to occur, and ``nodes'' where the electric fields weaken each other are more likely to occur. Therefore,
With this configuration, "antinodes" where the electric fields of the standing waves strengthen each other are less likely to occur on the processed object at the position where the side with the smaller reflection phase faces each other, and "nodes" where the electric fields weaken each other are more likely to occur. As a result, it is difficult for microwaves to concentrate on at least a part of the object to be processed (the part that does not want to be processed).In other words, the shielding performance for shielding microwaves can be improved compared to the conventional method, and the part that does not want to be processed is You can prevent the process from proceeding.

The microwave processing apparatus of the present invention is arranged such that the side with a small reflection phase faces at least a part of the object to be processed (the part that is not desired to be processed), so that It is possible to make objects less likely to have "antinodes" where the electric fields of standing waves strengthen each other, and more likely to form "nodes" where the electric fields weaken each other. In other words, the shielding performance for shielding microwaves can be improved compared to the conventional method, and it is possible to prevent processing of parts that are not desired to be processed.

Configuration diagram of a microwave processing device in Embodiment 1 of the present invention FIG. 2 is a detailed configuration diagram of the microwave shielding device in FIG. It is a characteristic diagram of a planar patch resonator, (a) a characteristic diagram in which the vertical axis is a reflection phase, (b) a characteristic diagram in which the vertical axis is a characteristic diagram in which the absolute value of the reflection phase is shown. Illustration of the influence of the position of the planar patch resonator on the electric field in the processing chamber Characteristic diagram showing the ratio of temperature rise in two glasses of water when changing the antenna orientation and microwave shielding device in Figure 1 Image diagram explaining why the shielding performance of the microwave shielding device of the present invention is good Configuration diagram of a microwave processing device in Embodiment 2 of the present invention Characteristic diagram showing the ratio of temperature rise of two glasses of water when changing the microwave shielding device in Figure 7

(The circumstances that led to this disclosure)
In a microwave oven, which is a typical microwave processing device, when food that you want to heat and food that you do not want to heat, such as Makunouchi bento, are placed in the same container, you can transfer only the food that you want to heat to another plate. You probably don't want to do anything like reheating the food because it will stain other plates, ruin the beautiful presentation, and above all, it will be more work. In such cases, it is desirable to have a microwave shielding device that can shield microwaves with the simple task of covering food that you do not want to heat, for example. However, in the conventional microwave shielding device, as shown in Patent Document 1, a material layer that reflects or absorbs microwaves is formed inside the container, and in addition, it is completely covered with a lid. This requires the user to prepare a special container and mold the food to fit the shape of the container before serving, which is not an easy task at all.

On the other hand, even if a material that reflects or absorbs microwaves is used, as in Patent Document 1, if the material is not completely covered but only covers the food, the microwaves may enter through the uncovered gap and damage the food. becomes warm. In particular, when microwaves that have looped around become standing waves, creating a "belly" where the electric fields strengthen each other, the food located in the "belly" gets warmer than expected. In other words, the shielding performance of conventional microwave shielding devices is insufficient.

Therefore, the present inventors investigated a configuration that can improve the shielding performance of the microwave shielding device, and particularly focused on the reflection phase. The reflected phase is the shift in the phase of the microwave after it is reflected (reflected wave) from the phase before it hits the material (incident wave). ), the reflection phase is known to be 180 degrees, and is sometimes said to be ``the phase is reversed when it hits metal.''

Here, since the microwave is a wave, the phase repeats once in 360 degrees, but it can be said that it repeats changes within a range of ±180 degrees when the phase is 0 degrees. In this case, +180 degrees and -180 degrees are both the farthest from 0 degrees, and "180 degrees" when both are expressed as absolute values can be said to be the maximum value of the phase shift from 0 degrees. From the above, when discussing the phase difference between two conditions (in the present invention, the reflection phase of the reflected wave relative to the incident wave), the minimum value is 0 degrees (same phase) and the maximum value is 180 degrees (opposite phase). Therefore, the reflection phase is a value between 0 degrees and 180 degrees.

The present inventors investigated making the reflection phase smaller than 180 degrees of general metal materials, and found that the smaller the reflection phase, the more the electric fields of the standing waves strengthen each other in the vicinity of the reflecting surface. It was discovered that this phenomenon is difficult to occur, and that the electric field tends to become ``nodes'' where they weaken each other. Based on these new findings, the present inventors have arrived at the following disclosure.

A microwave shielding device according to a first aspect of the present invention is a microwave processing device that processes an object to be processed in a processing chamber by irradiating microwaves, and is arranged in the processing chamber so that the side with a smaller reflection phase is directed toward the object to be processed. It is arranged so as to face at least a portion (a portion that is not desired to be processed).

Here, we discovered that on the side of the microwave shielding device where the reflection phase is small, ``antinodes'' where the electric fields of standing waves strengthen each other are less likely to occur, and ``nodes'' where the electric fields weaken each other are more likely to occur. Therefore, with this configuration, "antinodes" where the electric fields of the standing waves strengthen each other are less likely to occur on the processed object at the position where the side with the smaller reflection phase faces each other, and "nodes" where the electric fields weaken each other are more likely to occur. Therefore, as a result, it is difficult for microwaves to concentrate on at least a part of the object to be processed (parts that do not want to be processed).In other words, the shielding performance for shielding microwaves can be improved compared to the conventional method, and it is possible to prevent microwaves from being processed. You can prevent a portion of the process from proceeding.

In addition to the first invention, the microwave shielding device of the second invention has a structure in which the front side and the back side have different reflection phases, and the back side with the smaller reflection phase is disposed facing the object to be processed.

As a result, "antinodes" where the electric fields of the standing waves strengthen each other are less likely to occur on the workpiece where the back sides with small reflection phases face each other, and "nodes" where the electric fields weaken each other are more likely to occur. As a result, it is difficult for microwaves to concentrate on at least a part of the object to be processed (the part that does not want to be processed).In other words, the shielding performance for shielding microwaves can be improved compared to the conventional method, and the part that does not want to be processed is You can prevent the process from proceeding.

In the microwave shielding device of the third invention, in addition to the second invention, the object to be processed has a region to be processed and a region not to be processed, and it is not desired to process the back side of the object where the reflection phase is small. It is configured to be placed facing the body part.

As a result, "antinodes" where the electric field of the standing wave strengthens each other are less likely to occur in the parts of the workpiece that are not desired to be processed, where the back sides with small reflection phases face each other, and "nodes" where the electric fields weaken each other are more likely to occur. As a result, microwaves are less likely to concentrate on the parts of the object that do not want to be processed.In other words, the shielding performance for shielding microwaves can be improved more than before, and the parts that do not want to be processed can be You can prevent the process from proceeding.

In addition to the third invention, the microwave shielding device of the fourth invention has a plurality of objects to be processed, a first object to be processed and a second object to be not desired to be processed, The structure is such that the back side with a small reflection phase faces the second object to be processed.

As a result, on the second processed object whose back side faces the opposite side with a small reflection phase, "antinodes" where the electric fields of the standing waves strengthen each other are less likely to occur, and "nodes" where the electric fields weaken each other are more likely to occur. As a result, it is difficult for microwaves to concentrate on the second object to be processed, which means that the shielding performance for shielding microwaves can be improved compared to the conventional method, and the second object to be processed, which is not to be processed, You can prevent things from progressing.

A microwave shielding device according to a fifth invention, in addition to the fourth invention, wherein the microwave processing device is a microwave oven that heats an object by irradiating microwaves to the object to be processed, and the object to be processed is food. It has a first food that you want to heat-process (such as a prepared dish) and a second food that you do not want to heat-process (such as raw vegetables or pickles), and is arranged with the back side with a small reflection phase facing the second food. This structure suppresses heating of the second food.

As a result, for the second food whose back side faces the one with a small reflection phase, it is difficult to form an "antinode" where the electric field of the standing wave strengthens each other, and it is possible to make it more likely to form a "node" where the electric field weakens each other. Microwaves are less likely to concentrate on the second food that you do not want to heat-process.In other words, the shielding performance for shielding microwaves can be improved more than before, making it possible to heat-process the second food that you do not want to heat-process. can be prevented from proceeding.

A microwave shielding device according to a sixth invention, in addition to any one of the first to fifth inventions, has a conductive member with a reflection phase of approximately 180 degrees on the front side, and a resonance with a reflection phase of approximately 0 degrees on the back side. The structure has members.

As a result, the microwave resonates with the resonant member on the back side, making it possible to reduce the reflection phase. However, by setting the reflection phase to the minimum of approximately 0 degrees, the object to be processed at the position where the back side faces is exposed to the standing wave. Since it is possible to make "antinodes" where electric fields strengthen each other the least likely to occur, and "nodes" where electric fields weaken each other most easily, as a result, at least a part of the object to be processed (the part that you do not want to treat) is most likely to be exposed to microwaves. can make it difficult to concentrate. In addition, the front side is a conductive material with a reflection phase of approximately 180 degrees, so like a general metal plate, it reflects microwaves that come from a distance toward the parts of the object that you do not want to process, so it is even more effective. You can prevent waves from coming. By combining these two effects, the shielding performance for shielding microwaves can be improved compared to the conventional method, and it is possible to prevent processing of parts that are not desired to be processed.

In addition to any one of the first to sixth inventions, there is a microwave shielding device according to a seventh invention, in which the resonant member is a planar patch resonator, and a conductive member (reference surface) on the front side having a large area has a conductive member having a narrow area. The second conductive member (patch surface) is arranged to resonate from the back side.

As a result, it is possible to cause resonance in a narrow space where the reference surface and the patch surface face each other in close proximity, and the entire structure can be formed into a thin planar shape.

In addition to the seventh invention, the microwave shielding device of the eighth invention is characterized in that the length of the second conductive member (patch surface) in at least one direction is an integral multiple of 1/2 of the running length of the microwave. It is said that

As a result, among the electric fields in various directions generated by the microwave, the electric field component in the direction that coincides with at least one direction of the second conductive member (patch surface) is transferred to the microwave of the second conductive member (patch surface). Since resonance occurs with a length that is an integral multiple of 1/2 of the effective length of the wave, resonance can be reliably achieved with this configuration.

In addition to the seventh invention, a microwave shielding device according to a ninth invention has a structure in which the front conductive member and the second conductive member are covered with an insulator so as not to be exposed.

As a result, for example, when the microwave processing device is a microwave oven, the wall surface forming the processing chamber may be a conductive member, but the conductive member on the front side of the microwave shielding device or the second conductive member Since it is covered with an insulator to prevent it from being exposed, it is possible to secure an insulation distance between the front conductive member or second conductive member and the conductive member on the wall of the processing chamber, preventing unsafe conditions such as sparks. can be avoided from happening. Additionally, if the front conductive member and the second conductive member are exposed, they may rust or come in contact with food and become unsanitary, but it is possible to reduce such risks. can.

In addition to the ninth invention, a microwave shielding device according to a tenth invention has a structure in which the insulator also serves as a plate.

Thereby, it is easy to place the object to be processed on the dish, and the object to be processed can be placed facing the dish, ie, the microwave shielding device, without much difficulty. In particular, plastic, glass, ceramics, etc. can be considered as the insulator that constitutes the plate, but since it is possible to print patterns and characters on the surface of any of them, it is possible to place the part of the object to be processed that does not want to be processed, that is, the reflection phase. If the insulator on the smaller side is marked by printing or the like, the user can place the parts of the object to be processed that the user does not want to process accordingly. Further, the object to be processed comes into contact with the insulating plate but does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the dish.

In addition to the ninth invention, the microwave shielding device of the eleventh invention has a structure in which the insulator also serves as a container.

Thereby, it is easy to place the object to be processed in the container, and the object to be processed can be placed facing the container, that is, the microwave shielding device, without much difficulty. In particular, plastic, glass, ceramics, etc. can be considered as the insulator that makes up the vessel, but since it is possible to print patterns and characters on the surface of any of them, it is possible to place the part of the object to be processed that does not want to be processed, that is, the reflection phase. If the insulator on the smaller side is marked by printing or the like, the user can place the parts of the object to be processed that the user does not want to process accordingly. Further, the object to be processed comes into contact with the insulating container, but does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the container.

In addition to the ninth invention, a microwave shielding device according to a twelfth invention has a structure in which the insulator also serves as a lunch box.

Thereby, it is easy to place the object to be processed in the lunch box, and the object to be processed can be placed facing the lunch box, that is, the microwave shielding device, without much effort. In particular, plastic, glass, ceramics, etc. can be considered as the insulators that make up the lunch box, but since it is possible to print patterns and letters on the surface of any of them, it is possible to place the parts of the object to be processed that do not want to be processed, i.e. reflective. If the insulator on the side where the phase is smaller is marked by printing or the like, the user can place the parts of the object to be processed that he or she does not want to process accordingly. Furthermore, the object to be treated comes into contact with the insulating lunch box, but does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the lunch box.

In addition to the ninth invention, a microwave shielding device according to a thirteenth invention has a structure in which the insulator also serves as a lid.

Thereby, it is easy to put the lid on the object to be treated, and the object to be treated can be placed opposite the lid, ie, the microwave shielding device, without much difficulty. In particular, plastic, glass, ceramics, etc. can be considered as the insulator that constitutes the lid, but since it is possible to print patterns and characters on the surface of any of them, it is possible to place the cover over the part of the object that you do not want to process, that is, the reflection phase. If the insulator on the smaller side is marked by printing or the like, the user can cover the part of the object to be processed that the user does not want to process accordingly. Further, although the object to be processed may come into contact with the insulating lid, it does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the lid.

In addition to the ninth invention, the microwave shielding device according to the fourteenth invention has a structure in which the insulator also serves as a wrap.

Thereby, it is easy to put the wrap on the object to be treated, and the object to be treated can be placed opposite the wrap, that is, the microwave shielding device, without much difficulty. In particular, a transparent resin material can be considered as the insulator that constitutes the wrap, but since it is possible to see through the contents, it is possible to see through the position where it is placed over the part of the object that is not to be treated, that is, the side where the reflection phase is small. If this is done, the user can cover the parts of the object that the user does not want to process accordingly. Further, although the object to be processed may come into contact with the wrap of the insulator, it does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the wrap.

In addition to the ninth invention, a microwave shielding device according to a fifteenth invention has a structure in which the insulator also serves as a bag.

Thereby, it is easy to put the object to be processed into the bag, and the object to be processed can be placed facing the bag, that is, the microwave shielding device, without much effort. In particular, a resin material is considered as the insulator that constitutes the bag, but since it is possible to print patterns and characters on the surface, the part of the object to be processed that does not want to be processed should be placed in the opposite position, that is, on the side where the reflection phase is small. If the insulator is marked by printing or the like, the user can place the parts of the object to be processed facing each other accordingly. Alternatively, a transparent resin material may be used as the insulator for the bag, but in this case, the contents can be seen through, so the position where the part of the object to be processed that is not to be processed should be facing, that is, the reflection phase is By allowing the smaller side to be seen through, the user can place the parts of the object that he or she does not want to process facing each other accordingly. Furthermore, the object to be processed comes into contact with the insulating bag, but does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the trouble of preparing a microwave shielding device separate from the bag.

Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to this embodiment.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 6. FIG. 1 is a block diagram of the microwave processing device of the present invention, and FIG. 2 is a detailed block diagram of the microwave shielding device of FIG. A-A sectional view, Figure 3 is a characteristic diagram of a planar patch resonator, where (a) the vertical axis is a characteristic diagram of the reflection phase, (b) the vertical axis is a characteristic diagram of the absolute value of the reflection phase, and Figure 4 is a characteristic diagram of the reflection phase. An explanatory diagram of the influence of the position of the planar patch resonator on the electric field in the processing chamber. Figure 5 is a characteristic diagram showing the ratio of temperature rise of two glasses of water when the antenna orientation and microwave shielding device are changed in Figure 1. , FIG. 6 is an image diagram explaining the reason why the microwave shielding device of the present invention has good shielding performance.

FIG. 1 is a cross-sectional configuration diagram of the microwave processing apparatus of the present invention viewed from the front. A microwave oven 1 as a typical microwave processing device has a processing chamber 2 surrounded by a wall made of a conductive material to prevent microwaves from leaking to the outside, and a processing chamber 2 for emitting microwaves into the processing chamber 2. A magnetron 3 is a typical microwave generation means, a waveguide 4 transmits the microwaves emitted from the magnetron 3, and the microwaves in the waveguide 4 are connected to the waveguide 4 to be transferred to the processing chamber 2. An antenna 5 that irradiates the antenna 5, a motor 6 that is a drive means that rotates the antenna 5, a control means 7 that controls the operation of generating and stopping the microwave of the magnetron 3 and the rotation and stopping operation of the motor 6, and a typical workpiece. The processing chamber 2 includes a mounting table 8 on which a food product is placed within the processing chamber 2, and the like. The mounting table 8 is made of a low-loss dielectric material (eg, glass, ceramic, etc.) because it is desired that the microwave irradiated from the antenna 5 below be transmitted and irradiated onto the food with as little loss as possible.

Here, the foods to be processed include a first food 9 to be heat-processed, a second food 10 not to be heat-processed, placed on a mounting table 8, and a second food 9 not to be heat-processed to be processed. A microwave shielding device 11 is placed under the food 10.

The antenna 5 is mainly made of a conductive material, but has a structure that allows microwaves 14 and 15 to be easily irradiated from the horn portion 12 and the opening 13. In the state shown in FIG. Since both antennas 15 are directed to the left, it can be said that the antenna 5 in the state shown in FIG. 1 has directivity to the left. The antenna 5 is normally rotated by a motor 6 to change its direction and change the direction of microwave irradiation from moment to moment. It is controlled to prevent uneven heating. However, when the first food 9 to be heat-treated and the second food 10 not to be heat-treated are clear as in this embodiment, when the antenna 5 is oriented as shown in FIG. It is also conceivable to stop the heating process and heat only the first food 9 to be heat-treated using the microwaves 14 and 15. In this case, it is possible to preferentially heat the first food 9 to be heated to some extent, but this may not be sufficient in some cases.

The first reason why it is not sufficient is that it is difficult to irradiate all the microwaves 14 and 15 only to the first food 9 to be heat-treated. It is conceivable that the microwaves that did not hit the first food 9 to be heat-treated are reflected from the wall surface of the processing chamber 2 and hit the second food 10 that is not to be heat-processed, heating them. Further, unless absorbed by either the first food 9 or the second food 10, the microwaves will be reflected many times on the wall surface and will generate standing waves within the processing chamber 2. When a standing wave is generated, ``antinodes'' where the electric field strengthens each other and ``nodes'' where the electric field weakens each other occur periodically, and food located in the ``belly'' is more likely to be heated, and food located in the ``nodes'' is less likely to be heated. Become. Therefore, if a "belt" of the standing wave occurs at a position of the second food 10 that is not desired to be heat-processed, it will be heat-processed even though it is not desired to be heat-processed. Suppose that the position of the second food 10 that you do not want to heat-process is at the "belt" of the standing wave, and the position of the first food 9 that you want to heat-process is the "node" of the standing wave. A reversal phenomenon may also occur in which the second food 10, which is not desired to be heat-treated, is heat-treated more than the food 9.

The second reason why it is not sufficient is that even if the microwave hits the first food 9 to be heat-treated, not all of it will be absorbed. Even when microwaves hit the first food 9 to be heat-treated, some percentage of the microwaves are reflected by the surface of the first food 9 to be heat-treated, and the microwaves do not affect the first food 9 to be heat-treated. It is assumed that even if it gets inside, it will not be able to absorb everything and it will pass through. As mentioned in the first reason, the microwaves reflected on the surface of the first food 9 to be heat-treated or the microwaves transmitted through the first food 9 to be heat-treated are It may be reflected off the wall surface of the second food item 10 and hit the second food item 10 which is not desired to be heated, or it may cause standing waves.

The third reason why it is not sufficient is that the microwaves irradiated from the antenna 5 are not only the microwaves 14 and 15. Only the microwaves 14 and 15 are dominant, and there is also a possibility that the microwave 18 leaks backward from the gap between the rear flange 16 of the antenna 5 and the bottom wall 17 of the processing chamber 2. In order to rotate the antenna 5 with the motor 6, a gap is inevitably created between the antenna 5 and the bottom wall 17, and a small amount of microwave will leak in an unintended direction. There is a possibility that the leakage of microwaves such as 18 may directly hit the second food 10 that is not to be heat-processed, or it may be reflected off the wall of the processing chamber 2, similar to the first and second reasons. There is also a possibility that the second food 10 that is not desired to be heated may be hit or a standing wave may be caused.

The microwave shielding device 11 is effective against such problems. FIG. 2 is a detailed configuration diagram of the microwave shielding device of FIG. 1, where FIG. 2(a) is a configuration diagram seen from above, and FIG. 2(b) is a sectional view taken along line AA in FIG. 2(a). 19 is an external image of the second food 10 (not shown) that is not desired to be heat-processed and is shown with a broken line for reference. The area is larger and provides a better shielding effect.

The microwave shielding device 11 has different structures on the front side and the back side, and in order from the front side (here, the bottom side of the paper in FIG. 2(b) is defined as the front side), a conductive member 20 with a large area, a dielectric material 21. Periodically arranged second conductive members 22 with a narrow area are integrally formed, and an insulator 23 covering the whole forms a thin plate shape. It is also considered that it constitutes a plate on which the second food item 10 that is not wanted is placed. The conductive member 20, which has a large surface area, is made of a general metal material such as aluminum or copper, so that the reflection phase is approximately 180 degrees, and the microwaves coming from below in FIGS. 1 and 2(b) It has the function of total reflection. The second conductive members 22 with a narrow area on the back side are arranged periodically and form a planar patch resonator that resonates by facing the conductive member 20 with a wide area via the dielectric 21, It is a resonant member with a reflection phase of approximately 0 degrees.

Therefore, the second conductive member 22 having a narrow area can be called a patch. This patch (second conductive member 22 with a narrow area) can also be made of general metal materials such as aluminum and copper, and the dielectric material 21 can be made of Teflon (registered trademark), ceramic, glass, etc. It is possible to construct it from a low loss material.

More specifically, it is also possible to configure the microwave shielding device 11 with a double-sided substrate for high frequencies. For example, the conductive member 20 having a large area and the second conductive member 22 having a narrow area are formed using a pattern of copper foil on a double-sided board, and the dielectric body 21 is formed from a substrate material (Teflon (registered trademark), glass epoxy, etc.). You can also do that. In such a case, the conductive member 20 having a large area may be referred to as a reference surface, the second conductive member 22 having a narrow area may be referred to as a patch surface, and so on.

Furthermore, when considering a double-sided board, it is easy to consider using a moisture-proof resin molding material as the insulator 23. Now, in order to make the planar patch resonator resonate, the vertical and horizontal lengths of the second conductive member 22, which has a narrow area, must be adjusted appropriately according to the dielectric constant and thickness of the dielectric material 21. No. The same concept as the technology for microstrip lines made of general double-sided substrates can be applied to this, and the length of the patch surface in the direction of the current flowing through the patch surface is an integral multiple of 1/2 of the microwave run length. It's fine if you do this.

In this embodiment, nine second conductive members 22 having a narrow area are arranged in a square shape as shown in FIG. The length is set to approximately 1/2 of the microwave run length so that the length of the microwave is approximately 1/2. Thereby, with respect to FIG. 2(a), it is possible to cause resonance in both the horizontal direction of the plane of the paper and the current in the vertical direction of the plane of the paper.

FIG. 3 is a characteristic diagram of a planar patch resonator, in which (a) the vertical axis is a characteristic diagram of the reflection phase, and (b) the vertical axis is a characteristic diagram of the absolute value of the reflection phase. As shown in FIG. 3(a), the vertical axis represents the reflection phase when viewed from the back side, that is, the second conductive member 22 having a narrow area, and the horizontal axis represents the frequency. In the case of a microwave oven, the frequency band of microwaves generated from microwave generating means such as magnetron 3 is said to be 2.4 GHz to 2.5 GHz, but in that range the reflection phase varies from around +180 degrees to -180 degrees. It is a characteristic that changes in the vicinity.

This characteristic is a characteristic when the resonance frequency of the planar patch resonator is 2.45 GHz. Figure 3 (b) shows the reflection phase on the vertical axis in Figure 3 (a) as an absolute value, and for most frequencies in the frequency range (2 GHz to 3 GHz) on the horizontal axis, the absolute value of the reflection phase is 180 degrees. However, the reflection phase is 0 degrees only near 2.45 GHz, indicating resonance.

FIG. 4 is an explanatory diagram of the influence of the position of the planar patch resonator on the electric field within the processing chamber. From the top of FIG. 4, the analytical model, the electric field of the observation surface 24, the electric field of the observation surface 25, and the influence of the planar patch resonator are described. The analytical model has a configuration in which a waveguide 27 is connected to a processing chamber 26 as in FIG. 1, but it should be noted that the entire structure is shown upside down compared to FIG. The observation surface 24 is a cross section of the central portion of the processing chamber 26 in the front-rear direction. The observation surface 25 is a surface located on the left side of the processing chamber 26 in the left-right direction and perpendicular to the observation surface 24 . How far to the left the observation surface 25 should be placed will be described later. Further, both the electric field of the observation surface 24 and the electric field of the observation surface 25 are expressed as a constant electric field strength diagram. For example, 28 in the figure has a strong electric field and can be said to be the antinode of a standing wave.

Three types of analysis, A, B, and C, were performed in order from the left in FIG. 4, and A. No resonator (zero planar patch resonators), B. One planar patch resonator 29 is arranged at the center of the processing chamber 26 in the front-rear direction, C. An analysis was performed in which two planar patch resonators 29 were placed off the center of the processing chamber 26 in the front-rear direction, one at the back and the other at the front.

To determine how far to the left the observation surface 25 should be placed, we first performed an analysis without the resonator A, looked at the electric field distribution on the observation surface 24, and determined how far to the left the observation surface 25 should be placed. A position facing the antinode 30 of the standing wave was selected on the wall surface on which the vessel 29 was to be placed. The observation plane 25 was defined as a plane that passes through the center of the antinode 30 of the standing wave of the observation plane 24 and is orthogonal to the observation plane 24. At this time, when looking at the electric field distribution on the observation surface 25, it can be seen that an antinode 31 of the standing wave occurs at the intersection with the observation surface 24, which is definitely an antinode of the standing wave.

Here, focusing on the electric field of the observation surface 24 and the electric field of the observation surface 25, the effect of the planar patch resonator 29 will be considered by examining the changes at B and C where the resonator is present, with A having no resonator as a reference.

First, in A, the electric field distributions on both the observation plane 24 and the observation plane 25 are symmetrical with respect to the plane of the paper. Next, in B, the electric field becomes weaker at the same position where the antinodes 30 and 31 of the standing wave occurred in A, and especially when looking at the electric field on the observation surface 25, it is clear that the node 32 of the standing wave occurs. being changed. Furthermore, the left-right symmetry of the electric field on the observation surface 24 is beginning to collapse. In this B, one planar patch resonator 29 is placed at the center of the observation surface 25 in the longitudinal direction, and this is the position of the intersection of the observation surfaces 24 and 25, that is, the antinode of the standing wave at A. 30 and 31, it is considered that the planar patch resonator 29 weakens the antinode 30 of the standing wave and changes it so that it approaches the node.

This is because, according to the characteristics shown in Figure 3, the reflection phase of the patch surface of the rectangular patch resonator at 2.45 GHz is approximately 0 degrees, and the phase difference between the wave incident on the patch surface and the wave reflected by the patch surface is approximately 0 degrees. 0 degree, and considering that the phase difference between the incident wave and the reflected wave on a normal metal wall surface is 180 degrees, there is a difference between normal and normal near where the planar patch resonator 29 is placed. This means that a standing wave distribution has been formed.

In addition, when the reflection phase is approximately 0 degrees, it can be said that the impedance is infinite if expressed as an impedance, and the amount of high-frequency current that attempts to flow through the patch surface is suppressed, and the amount of high-frequency current flowing through the patch surface is suppressed. It is thought that the microwave acts to move away from the space. This is the cause of weakening the electric field in the vicinity of the planar patch resonator 29, and it is presumed that the left-right symmetry of the electric field on the observation surface 24 is collapsing due to its influence.

Next, in C, antinodes 30 and 31 of the standing wave occur, and there is almost no difference compared to A. In C, two planar patch resonators 29 are placed off-center in the front-rear direction, one in the back and one in front, and this position corresponds to the position facing the standing wave nodes 33 and 34 in A. In other words, the planar patch resonator 29 is placed opposite the node (weak spot) of the standing wave, and it is considered that the planar patch resonator 29 placed at the node of the standing wave (that is, a position where there is almost no electric field) has little influence.

To summarize the above, as shown in the bottom row of FIG. 4, when the planar patch resonator 29 is placed facing the antinode of the standing wave as shown in B, the "antinode" changes to a "node" and as shown in C. When the planar patch resonator 29 is placed opposite the node of the standing wave, the "node" is maintained as a "node". In other words, it was confirmed that when the planar patch resonators 29 are arranged, the opposing positions always become "nodes".

FIG. 5 shows a first food (workpiece) 9 to be heat-processed and a second food to be heat-processed when the orientation of the antenna 5 and the type of microwave shielding device 11 in the configuration of FIG. 1 are changed. FIG. 2 is a characteristic diagram quantitatively evaluating the microwaves irradiated to each of the foods (objects to be processed) 10 of FIG. The first food item 9 and the second food item 10 are the temperature of two cups of water (two cups) on the left and right when the same amount (200cc) of water in the same type of cup is heated at 600W for 30 seconds. It is a characteristic diagram showing the ratio of increase (temperature Te at the end of heating minus temperature Ts immediately before heating).

Here, it is known that the temperature rise of water is proportional to the power absorbed by water, and can be expressed as, for example, absorbed power P = 4.19 x quantity m x specific heat c x temperature rise (Te - Ts), When the quantity m (=200 cc) and the specific heat c (1 in the case of water) are the same as in this embodiment, the ratio of temperature rise matches the ratio of absorbed power. The ratio was determined by (temperature rise in second food 10)/(temperature rise in first food 9) based on the temperature rise in first food 9 on the left.

Therefore, it can be said that the smaller the numerical value of this ratio is, the higher the shielding performance of the microwave shielding device 11 is because the heat treatment of the second food (object to be treated) 10 that is not desired to be heat-treated is not progressed. In the bar graph shown in the upper part of FIG. 5, the vertical axis shows the ratio and the horizontal axis shows the four conditions, and since the ratio decreases as it goes to the right, it can be said that the shielding performance increases as it goes to the right. Details of the four conditions (combination of the orientation of the antenna 5 and the type of microwave shielding device 11) are listed below the bar graph.

To explain from left to right, the first condition is that the antenna 5 is rotating and there is no microwave shielding device, which is nothing but a normal use of a microwave oven, so the ratio is 0.91, which is close to 1. Foods 9 and 10 are heat-treated to the same extent.

The second result shows the directivity of the antenna 5 alone, with the antenna 5 facing left and no microwave shielding device, and the ratio is 0.45, so the second food 9 is the first food 9. 10 is reduced to about half the heat treatment.

The third condition is that the antenna 5 faces to the left and the microwave shielding device is an aluminum plate, which is the result of combining the directivity of the antenna 5 with the shielding performance of an aluminum plate, which is a common metal, and the ratio is 0.
．． 33, the heat treatment for the second food 10 is reduced to about 1/3 of that of the first food 9.

On the far right, the antenna 5 is directed to the left, and the planar patch resonator of the present invention is used as the microwave shielding device. This is the result of combining the directivity of the antenna 5 with the shielding performance of the microwave shielding device of the present invention. , the ratio is 0.31, so the heat treatment of the second food 10 is reduced the most compared to the first food 9. For reference, it can be said that the shielding performance is about 6% (=(1-0.31/0.33)×100) better than that of an aluminum plate, which is the third most common metal.

The reason why the microwave shielding device using the planar patch resonator of the present invention has better shielding performance than general metal will be explained using FIG. 6, although it is a qualitative image. In FIG. 6, the microwave shielding device 35 has a first conductive member 36 with a large area and a second conductive member (patch with a narrow area) 37, and is covered with an insulator 38. Further, a second food item 39 that is not desired to be heat-treated (an object to be processed that is not desired to be heated) is placed on the microwave shielding device 35 .

At this time, we will first discuss the shielding of microwaves traveling in the vertical direction. Microwaves 40 traveling from the bottom to the top cannot pass through the first conductive member 36, which has a large area, and are reflected downward as microwaves 41. Similarly, the microwave 42 traveling from above to the bottom cannot pass through the first conductive member 36 having a large area and is reflected upward as a microwave 43. The functions up to this point are the same as those of general metals, and with only the first conductive member 36 having a large area, the microwave shielding device 35 can secure a shielding effect equivalent to that of general metals.

Next, considering the standing wave, an antinode 44 of the standing wave occurs in the space below the microwave shielding device 35, but the vertical position of the antinode 44 of the standing wave has a large area. It tends to occur at a position a little away from the first conductive member 36 (for example, 1/4 of the wavelength ≒ 30 mm), and in the left-right direction 45, the periodicity is (for example, 1/2 of the wavelength≈60 mm pitch), etc. can be considered. However, since there is no food near the antinode 44 of this standing wave, the food is not heated. In this respect as well, it has the same effect as general metals.

However, the microwave shielding device 35 exerts its shielding effect in the space above the microwave shielding device 35 in FIG. For example, similar to the standing wave 44 in the space below the microwave shielding device 35, even if an antinode 46 of the standing wave is generated in the space above, a second conductive member (with a narrow area) is generated in the left-right direction 47. By arranging the patch) 37, as described above, an antinode is changed into a node and a node is maintained as a node, and as a result, an antinode 46 of the standing wave is less likely to occur in the left-right direction 47.

Therefore, the second food 39 that is not desired to be heat-processed (the object to be processed that is not desired to be heated), which is placed in a position facing the second conductive member (patch with a narrow area) 37, is stationary near the placement position. Since the antinode 46 of the wave is less likely to occur, as a result, the standing wave is less likely to be heated. In this respect, it can be said that the microwave shielding device 35 has a higher effect of shielding microwaves irradiated onto food than general metals.

In summary, the first embodiment of the present invention has the following effects.

(Corresponding to Claim 1) The microwave shielding device 11 of the present invention is disposed in the processing chamber 2 in a microwave processing device 1 that processes an object to be processed in the processing chamber 2 by irradiating it with microwaves. The side with a smaller phase (the side with the second conductive member 22 having a narrower area) is arranged so as to face at least a part of the object to be processed (the second food 10 that is not desired to be heat-treated).

Here, we believe that on the side of the microwave shielding device 11 where the reflection phase is small (the side where the second conductive member 22 with a narrow area is located), an "antinode" where the electric fields of the standing waves strengthen each other is less likely to occur, and the electric field We discovered that these tend to become "nodes" that weaken each other. Therefore, with this configuration, the object to be processed (the second food 10 that is not desired to be heat-treated) at the position where the side with the smaller reflection phase (the side where the second conductive member 22 with the narrower area is located) is opposed to the Since it is possible to make it less likely that the electric field in the wave will strengthen each other, and to make it more likely to form a node where the electric field weakens each other, at least part of the object to be processed (the second food item 10 that does not want to be heat-processed) ), it is difficult for microwaves to concentrate on the food, which means that the shielding performance for shielding microwaves can be improved more than before, and the processing of the parts that do not want to be processed (the second food that does not want to be heated) can be processed. You can avoid it.

(Corresponding to Claim 2) In addition, the microwave shielding device 11 of the present invention has a front side (the side where the conductive member 20 with a large area is located) and a back side (the side where the second conductive member 22 with a narrow area is located). The structure is such that the back side (the side where the second conductive member 22 having a narrow area is located), which has a different reflection phase and a small reflection phase, faces the object to be processed.

As a result, the electric field of the standing wave is strengthened on the object to be processed (the second food 10 that is not to be heat-processed) at the position where the back side (the second conductive member 22 with a narrow area) with a small reflection phase faces the object. Since it is possible to make it difficult for "bellies" to occur and to easily form "nodes" where the electric field weakens each other, as a result, at least a part of the object to be processed (the second food 10 that does not want to be heat-treated) is exposed to microwaves. It is difficult to concentrate the microwaves, that is, the shielding performance for shielding microwaves can be improved more than before, and it is possible to prevent processing of parts that are not desired to be processed (second food 10 that is not desired to be heat-processed). can.

(Corresponding to Claim 3) In addition, the microwave shielding device 11 of the present invention includes a part to be processed (the first food 9 to be heat-treated) and a part not to be processed (the second part not to be heat-processed). food 10) with a small reflection phase (the side where the second conductive member 22 with a narrow area is located) is the part of the object to be processed that is not desired to be processed (the second food 10 that is not desired to be heat-processed). The structure is such that it is placed towards the

As a result, the back side with a small reflection phase (the side where the second conductive member 22 with a narrow area is located) is placed on the part of the object to be processed that is not desired to be processed (the second food 10 that is not desired to be heat-processed) at the opposing position. , it is possible to make it difficult for the standing waves to form "antinodes" where the electric fields strengthen each other, and to make it easier to form "nodes" where the electric fields weaken each other. It is difficult for microwaves to concentrate on the second food 10), that is, the shielding performance for shielding microwaves can be improved compared to the conventional method, and the parts that do not want to be processed (second food 10) that do not want to be heated are ) can be prevented from proceeding.

(Corresponding to Claim 4) In addition, the microwave shielding device 11 of the present invention has a plurality of objects to be processed, including a first object to be processed (first food 9 to be heat-processed) and an object to be processed that is not to be processed. It has a second object to be processed (second food 10 that is not desired to be heat-treated) and is arranged with the back side having a small reflection phase facing the second object to be processed (second food 10 that is not desired to be heat-processed). It is configured to do this.

As a result, the second object to be processed (the second food 10 that is not to be heat-treated), whose back side with a small reflection phase (the side where the second conductive member 22 with a narrow area is located) faces, is exposed to a standing wave. As a result, it is possible to prevent the occurrence of "bellies" where the electric fields strengthen each other, and to make it easier to form "nodes" where the electric fields weaken each other. In 10), it is difficult for microwaves to concentrate, that is, the shielding performance for shielding microwaves can be improved compared to conventional methods, and the processing of parts that do not want to be processed (second food 10 that is not desired to be heat-processed) is possible. You can prevent it from proceeding.

(Corresponding to Claim 5) In the microwave shielding device 11 of the present invention, the microwave processing device 1 is a microwave oven that heats an object by irradiating microwaves onto the object to be processed, and the object to be processed is food. , has a first food 9 to be heat-treated (such as a prepared dish) and a second food 10 not to be heat-treated (such as raw vegetables or pickles), and has a back side with a small reflection phase (a second food with a narrow area). By arranging the side (on which the conductive member 22 is located) facing the second food 10, heating of the second food 10 is suppressed.

As a result, on the second food 10 whose back side with a small reflection phase (the side with the second conductive member 22 with a narrow area) faces, an "antino" where the electric fields of the standing waves strengthen each other is less likely to occur, and the electric field As a result, it is difficult for microwaves to concentrate on the second food 10 that is not desired to be heat-treated, that is, the shielding performance for shielding microwaves is improved more than before. Therefore, it is possible to prevent the heat treatment of the second food 10 that is not desired to be heat-treated.

(Corresponding to Claim 6) The microwave shielding device 11 of the present invention additionally has a conductive member (conductive member 20 with a large area) with a reflection phase of approximately 180 degrees on the front side, and a conductive member with a reflection phase of approximately 180 degrees on the back side. The configuration includes a 0 degree resonance member (second conductive member 22 having a narrow area).

As a result, the microwave resonates with the resonant member on the back side (the second conductive member 22 with a narrow area), making it possible to reduce the reflection phase. On the object to be processed (the second food 10 that is not desired to be heat-processed) at a position opposite to the narrow second conductive member 22 (on the side where the narrow second conductive member 22 is located), "antinode" where the electric fields of the standing waves strengthen each other is least likely to occur. , it is possible to make it most likely to form "nodes" where the electric field weakens each other, and as a result, it is possible to make it most difficult for microwaves to concentrate on at least a part of the object to be processed (the second food 10 that is not desired to be heat-processed). Can be done. In addition, since the front side is a conductive member (conductive member 20 with a large area) with a reflection phase of approximately 180 degrees, it can be viewed from a distance in parts of the object that are not to be processed (heat-treated), just like a general metal plate. Since the microwaves coming towards the second food 10) are reflected, it is possible to further prevent the microwaves from coming. By combining these two effects, the shielding performance for shielding microwaves can be improved more than before, and the processing of the parts that do not want to be processed (the second food that does not want to be heated) is prevented from proceeding. can do.

(Corresponding to Claim 7) In addition, in the microwave shielding device 11 of the present invention, the resonant member is a planar patch resonator 29, and the front conductive member 20 (reference surface) having a large area has a second conductive member having a narrow area. The structure is such that resonance occurs by facing the sexual members 22 (patch surfaces) from the back side.

As a result, it is possible to cause resonance in a narrow space where the reference surface and the patch surface face each other in close proximity, and the entire structure can be formed into a thin planar shape.

(Corresponding to Claim 8) In addition, in the microwave shielding device 11 of the present invention, the length of the second conductive member 22 (patch surface) in at least one direction is an integer half the running length of the microwave. It is doubled.

As a result, among electric fields in various directions generated by microwaves, an electric field component in a direction that coincides with at least one direction of the second conductive member 22 (patch surface) is transmitted to the second conductive member 22 (patch surface). Since resonance occurs with a length that is an integral multiple of 1/2 of the effective length of the microwave, this configuration can ensure resonance.

(Corresponding to Claim 9) The microwave shielding device 11 of the present invention is additionally configured to cover the first conductive member 20 and the second conductive member 22 on the front side with an insulator 23 so that they are not exposed.

As a result, for example, when the microwave processing device 1 is a microwave oven, the wall surface forming the processing chamber 2 may be a conductive member, but the first conductive member 20 on the front side of the microwave shielding device 11 Since the conductive member 20 and the second conductive member 22 are covered with the insulator 23 so as not to be exposed, the gap between the first conductive member 20 and the second conductive member 22 on the front side and the conductive member on the wall of the processing chamber 2 is The insulation distance can be secured and unsafe conditions such as sparks can be avoided. Furthermore, if the first conductive member 20 and the second conductive member 22 on the front side are exposed, they may rust or come into contact with food, resulting in unsanitary conditions. can be reduced.

(Corresponding to Claim 10) The microwave shielding device 11 of the present invention is configured such that the insulator 23 also serves as a plate.

Thereby, it is easy to place the object to be processed on the dish, and the object to be processed can be placed facing the dish, that is, the microwave shielding device 11, without much effort. In particular, the insulator 23 constituting the plate can be made of plastic, glass, ceramics, etc., but it is possible to print patterns and letters on the surface of any of them, so the parts of the object to be processed that do not want to be processed (heat-treated If the position where the second food 10) is to be placed, that is, the upper insulator 23 on the side where the reflection phase is small, is marked by printing, etc., the user can mark the part of the object to be processed (heat-treated) according to the mark. It is also possible to place the second food item 10) that you do not want. Further, the object to be processed comes into contact with the insulating plate but does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the dish.

(Embodiment 2)
A microwave processing apparatus according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a cross-sectional configuration diagram of a microwave processing apparatus according to Embodiment 2 of the present invention viewed from the front. A microwave oven 48 as a typical microwave processing device has a processing chamber 49 surrounded by a wall made of a conductive material to prevent microwaves from leaking to the outside, and a processing chamber 49 for radiating microwaves into the processing chamber 49. A magnetron 50, which is a typical microwave generation means, a waveguide 52, which transmits the microwave 51 emitted from the magnetron 50 to the processing chamber 49, a plate 53, on which food, which is a typical object to be processed, is placed, and a plate. It has a motor 54 as a driving means for rotating the magnetron 53, a control means 55 for controlling the operation of generating and stopping the microwave of the magnetron 50, and the operation of rotating and stopping the motor 54. The plate 53 is made of a low-loss dielectric material (eg, glass, ceramic, etc.).

Here, the foods to be processed include a first food 56 to be heat-treated and a second food 57 not to be heat-treated, which are placed on the plate 53, but the second food 57 to be heat-treated is A microwave shielding device 58 is placed over the food 57.

Further, while the control unit 55 is irradiating the microwave 51 from the magnetron 50, the motor 54 rotates the plate 53, thereby also rotating the positions of the first food 56 and the second food 57. The wave shielding device 58 is always located above the second food product 57 that is not desired to be heat-treated, and exhibits a shielding effect throughout the heat treatment.

Incidentally, the microwave shielding device 58 may have a configuration similar to that of the first embodiment shown in FIG. 2, but care must be taken that the vertical direction when arranging it is different. That is, in FIG. 7 of this embodiment, although not shown, a conductive member with a large area is placed on the top surface, and a patch (a second conductive member with a narrow area) is placed on the bottom surface. It is therefore important that the patch (second conductive member with a narrow area) faces the second food product 57 that is not desired to be heat-treated.
In FIG. 2 of the first embodiment, the microwave shielding device is placed under the second food that is not to be heat-treated, so the patch (second conductive member with a narrow area) is placed upward so that it faces the food. In this embodiment shown in FIG. 7, the microwave shielding device is placed over the second food that is not desired to be heat-treated, so the patch (second conductive member with a narrow area) faces downward so as to face the food. It is to be placed in

FIG. 8 shows a first food (object to be processed) 56 to be heat-treated and a second food (object to be processed) not to be heat-processed when the microwave shielding device 58 is variously changed in the configuration shown in FIG. 7. 57 is a characteristic diagram showing a quantitative evaluation of the microwaves irradiated to each of the components. FIG. 8 is a characteristic diagram similar to FIG. 5 of the first embodiment, and the respective first food 56 and second food 57 are expressed as the same amount (200 cc) of water in the same type of cup. , is a characteristic diagram showing the ratio of temperature rise of two glasses of water (two glasses) on the left and right when heated at 600W for 30 seconds.Since the two glasses of water have the same volume and specific heat, the ratio of temperature rise is due to the absorbed power. matches the ratio of The ratio was determined by (temperature rise of second food 57)/(temperature rise of first food 56), based on the temperature rise of the first food (material to be processed) 56 to be heat-treated. . Therefore, it can be said that the smaller the numerical value of this ratio is, the higher the shielding performance of the microwave shielding device 58 is because the heat treatment of the second food (object to be treated) 57 that is not desired to be heat-treated is not progressed. In the bar graph shown in the upper part of FIG. 8, the vertical axis shows the ratio and the horizontal axis shows the three conditions, and the ratio decreases as you move to the right, so it can be said that the shielding performance increases as you move to the right. Below the bar graph, the details of the three conditions (all plates are rotated, the only difference is the microwave shielding device 58) are described.

Starting from the left, the first condition is that there is no microwave shielding device, and it is just a normal way to use a microwave oven, so the ratio is 1.0, and the first food 56 and the second food 57 are the same. Heat treated to a certain extent.

The second condition is that the microwave shielding device is an aluminum plate, and the result is due to the shielding performance of the aluminum plate, which is a common metal, and the ratio is 0.88, so the second food 57 is the same as the first food 56. The heat treatment is reduced by about 88%.

The far right is the condition where the planar patch resonator of the present invention is used as the microwave shielding device 58, and the results are based on the shielding performance of the microwave shielding device 58 of the present invention alone, and the ratio is 0.67, so the first It can be seen that the heat treatment of the second food 57 was reduced to about 67% compared to the food 56, and among these, the heat treatment was reduced the most. For reference, compared to the shielding performance of the second most common metal, aluminum plate, it can be said that the shielding performance is 24% (=(1-0.67/0.88)×100) better.

To summarize the above, the second embodiment of the present invention has the following effects.

(Corresponding to Claim 1) The microwave shielding device 58 of the present invention is disposed in the processing chamber 49 in a microwave processing device 48 that processes an object to be processed in the processing chamber 49 by irradiating it with microwaves. The side with a smaller phase (the side with the second conductive member having a narrower area) is arranged so as to face at least a portion of the object to be processed (the second food 57 that is not desired to be heat-treated).

Here, we believe that on the side of the microwave shielding device 58 where the reflection phase is small (the side where the second conductive member with a narrow area is located), an "antinode" where the electric fields of the standing waves strengthen each other is less likely to occur, and the electric field is I discovered that it is easy to form "nodes" that weaken each other. Therefore, with this configuration, a stationary Since it is possible to make it more likely that "belts", where the electric fields of the waves strengthen each other, and "nodes", where the electric fields weaken each other, as a result, at least part of the object to be processed (the second food 57 that does not want to be heat-processed) It is difficult for microwaves to concentrate on the food, that is, the shielding performance for shielding microwaves can be improved more than before, and the processing of parts that do not want to be processed (the second food 57 that is not desired to be heat-processed) does not proceed. You can do it like this.

(Corresponding to Claim 2) In addition, the microwave shielding device 58 of the present invention has a reflection phase on the front side (the side with the conductive member with a large area) and the back side (with the second conductive member with a narrow area). The structure is such that the back side (the side where the second conductive member having a narrow area is located), which has a small reflection phase, faces the object to be processed.

As a result, the electric fields of the standing waves strengthen each other on the object to be processed (the second food item 57 that does not want to be heat-processed) at the position where the back side (the second conductive member with a narrow area) with a small reflection phase faces the object. Since "belts" are less likely to occur and the electric field is more likely to form "nodes" that weaken each other, as a result, microwaves are concentrated on at least a part of the object to be processed (the second food 57 that does not want to be heat-processed). In other words, it is possible to improve the shielding performance for shielding microwaves than before, and prevent the processing of parts that are not desired to be processed (the second food 57 that is not desired to be heat-processed) to proceed. .

(Corresponding to Claim 3) In addition, the microwave shielding device 58 of the present invention includes a part to be processed (the first food 56 to be heat-processed) and a part not to be processed (the second part to be heat-processed). food 57) with a small reflection phase (the side where the second conductive member with a narrow area is located) is placed in the part of the object to be processed that is not desired to be processed (the second food 57 that is not desired to be heat-treated). The configuration is such that it is placed facing towards the target.

As a result, the part of the object to be processed that is not desired to be processed (the second food 57 that is not desired to be heat-processed) at the position where the back side with a small reflection phase (the side where the second conductive member with a narrow area is located) is facing is , it is possible to make it more difficult for the standing waves to form "antinodes" where the electric fields strengthen each other, and to make it easier to form "nodes" where the electric fields weaken each other. It is difficult for microwaves to concentrate on the second food 57), that is, the shielding performance for shielding microwaves can be improved more than before, and the parts that do not want to be processed (second food 57 that do not want to be heated) You can prevent the process from proceeding.

(Corresponding to Claim 4) In addition, the microwave shielding device 58 of the present invention has a plurality of objects to be processed, including a first object to be processed (first food 56 to be heat-processed) and a first object to be processed that is not to be processed. It has a second object to be processed (second food 57 that is not desired to be heat-treated) and is arranged with the back side having a small reflection phase facing the second object to be processed (second food 57 that is not desired to be heat-processed). It is configured to do this.

As a result, the second object to be processed (the second food 57 that does not want to be heat-processed), whose back side with a small reflection phase (the side where the second conductive member with a narrow area is located) faces, is exposed to standing waves. It is possible to prevent the formation of "belts" where the electric field strengthens each other, and to make it easier to form "nodes" where the electric field weakens each other. ), it is difficult for microwaves to concentrate on the food, which means that the shielding performance for shielding microwaves can be improved more than before, and processing of parts that do not want to be processed (second food 57 that does not want to be heat-processed) can be proceeded. You can avoid it.

(Corresponding to Claim 5) In the microwave shielding device 58 of the present invention, the microwave processing device 48 is a microwave oven that heats the object by irradiating microwaves onto the object to be processed, and the object to be processed is food. , has a first food 56 to be heat-treated (such as a prepared dish) and a second food 57 not to be heat-treated (such as raw vegetables or pickles), and has a back side with a small reflection phase (a second food with a narrow area). By arranging the side with the conductive member facing the second food 57, heating of the second food 57 is suppressed.

As a result, on the second food 57 whose back side with a small reflection phase (the side where the second conductive member with a narrow area is located) faces, an "antino" where the electric fields of the standing waves strengthen each other is less likely to occur, and the electric field is Since it is possible to easily form "knots" that weaken each other, as a result, it is difficult for microwaves to concentrate on the second food 57 that is not desired to be heat-processed, that is, the shielding performance for shielding microwaves can be improved more than before. As a result, it is possible to prevent the heat treatment of the second food 57 that is not desired to be heat-treated.

(Corresponding to Claim 6) The microwave shielding device 58 of the present invention additionally has a conductive member (a conductive member with a wide area) with a reflection phase of approximately 180 degrees on the front side, and a conductive member with a reflection phase of approximately 0 degrees on the back side. The structure has a resonant member (a second conductive member with a narrow area) of 100 kHz.

This makes it possible to reduce the reflection phase by causing the microwave to resonate with the resonant member on the back side (the second conductive member with a narrow area). On the object to be processed (the second food 57 that you do not want to heat-process) at the position where the second conductive member (on the side where the second conductive member is located) faces, "belts" where the electric fields of the standing waves strengthen each other are least likely to occur, and the electric field As a result, it is possible to make it most difficult for microwaves to concentrate on at least a part of the object to be processed (the second food 57 that is not desired to be heat-processed). . In addition, since the front side is a conductive member with a reflection phase of approximately 180 degrees (a conductive member with a large area), it can be viewed from a distance in areas of the object that you do not want to process (i.e., areas that you do not want to heat-process). Since the microwaves coming towards the second food 57) are reflected, it is possible to further prevent the microwaves from coming. By combining these two effects, it is possible to improve the shielding performance for shielding microwaves than before, and prevent the processing of parts that do not want to be processed (the second food 57 that does not want to be heated) to proceed. can do.

(Corresponding to Claim 7) In addition, in the microwave shielding device 58 of the present invention, the resonating member is a planar patch resonator, and the front conductive member (reference surface) having a large area has a second conductive member having a narrow area. (Patch surface) is configured to resonate by facing from the back side.

As a result, it is possible to cause resonance in a narrow space where the reference surface and the patch surface face each other in close proximity, and the entire structure can be formed into a thin planar shape.

(Corresponding to Claim 8) In the microwave shielding device 58 of the present invention, in addition, the length of the second conductive member (patch surface) in at least one direction is an integral multiple of 1/2 of the running length of the microwave. It is said that

As a result, among the electric fields in various directions generated by the microwave, the electric field component in the direction that coincides with at least one direction of the second conductive member (patch surface) is transferred to the microwave of the second conductive member (patch surface). Since resonance occurs with a length that is an integral multiple of 1/2 of the effective length of the wave, resonance can be reliably achieved with this configuration.

(Corresponding to Claim 9) The microwave shielding device 58 of the present invention is additionally configured to cover the front conductive member and the second conductive member with an insulator so that they are not exposed.

As a result, for example, when the microwave processing device 48 is a microwave oven, the wall surface forming the processing chamber 49 may be a conductive member. Since the conductive member is covered with an insulator so that it is not exposed, an insulating distance between the front conductive member or the second conductive member and the conductive member on the wall of the processing chamber 49 can be secured, thereby preventing sparks and other contaminants. A safe condition can be avoided. In addition, if the front conductive member and the second conductive member are exposed, they may rust or come into contact with food and become unsanitary, but such risks can be reduced. .

(Corresponding to Claim 13) The microwave shielding device 58 of the present invention is configured such that the insulator also serves as a lid.

Thereby, it is easy to put the lid on the object to be processed, and the object to be processed can be placed opposite the lid, that is, the microwave shielding device 58, without much difficulty. In particular, plastic, glass, ceramics, etc. can be considered as the insulator that constitutes the lid, but since it is possible to print patterns and characters on the surface of any of them, it is possible to place the cover over the part of the object that you do not want to process, that is, the reflection phase. If the upper insulator on the smaller side is marked by printing or the like, the user can cover the part of the object to be processed that the user does not want to process accordingly. Further, although the object to be processed may come into contact with the insulating lid, it does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the lid.

(Other embodiments)
(Corresponding to Claim 11) Note that the microwave shielding device of the present invention may have a structure in which the insulator also serves as a container.

Thereby, it is easy to place the object to be processed in the container, and the object to be processed can be placed facing the container, that is, the microwave shielding device, without much difficulty. In particular, plastic, glass, ceramics, etc. can be considered as the insulator that makes up the vessel, but since it is possible to print patterns and characters on the surface of any of them, it is possible to place the part of the object to be processed that does not want to be processed, that is, the reflection phase. If the upper insulator on the smaller side is marked by printing or the like, the user can place the parts of the object to be processed that he or she does not want to process accordingly. Further, the object to be processed comes into contact with the insulating container, but does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the container.

(Corresponding to Claim 12) Note that the microwave shielding device of the present invention may be configured such that the insulator also serves as a lunch box.

Thereby, it is easy to place the object to be processed in the lunch box, and the object to be processed can be placed facing the lunch box, that is, the microwave shielding device, without much effort. In particular, plastic, glass, ceramics, etc. can be considered as the insulators that make up the lunch box, but since it is possible to print patterns and letters on the surface of any of them, it is possible to place the parts of the object to be processed that do not want to be processed, i.e. reflective. If the upper insulator on the side where the phase is smaller is marked by printing or the like, the user can place the parts of the object to be processed that he or she does not want to process accordingly. Furthermore, the object to be treated comes into contact with the insulating lunch box, but does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the lunch box.

Furthermore, there is a possibility that the shielding performance is better than that of the food tray of Patent Document 1.

(Corresponding to Claim 14) Note that the microwave shielding device of the present invention may be configured such that the insulator also serves as a wrap.

Thereby, it is easy to put the wrap on the object to be treated, and the object to be treated can be placed opposite the wrap, that is, the microwave shielding device, without much difficulty. In particular, a transparent resin material can be considered as the insulator that constitutes the wrap, but since it is possible to see through the contents, it is possible to see through the position where it is placed over the part of the object that is not to be treated, that is, the side where the reflection phase is small. If this is done, the user can cover the parts of the object that the user does not want to process accordingly. Further, although the object to be processed may come into contact with the wrap of the insulator, it does not come into contact with the internal conductive member covered with the insulator, which is sanitary. Furthermore, it is possible to eliminate the need to prepare a microwave shielding device separate from the wrap.

(Corresponding to Claim 15) Note that the microwave shielding device of the present invention may have a structure in which the insulator also serves as a bag.

Thereby, it is easy to put the object to be processed into the bag, and the object to be processed can be placed facing the bag, that is, the microwave shielding device, without much effort. In particular, a resin material is considered as the insulator that constitutes the bag, but since it is possible to print patterns and characters on the surface, the part of the object to be processed that does not want to be processed should be placed in the opposite position, that is, on the side where the reflection phase is small. If the insulator is marked by printing or the like, the user can place the parts of the object to be processed facing each other accordingly. Alternatively, a transparent resin material may be used as the insulator for the bag, but in this case, the contents can be seen through, so the position where the part of the object to be processed that is not to be processed should be facing, that is, the reflection phase is By allowing the smaller side to be seen through, the user can place the parts of the object that he or she does not want to process facing each other accordingly. Furthermore, the object to be processed comes into contact with the insulating bag, but does not come into contact with the internal conductive member covered with the insulating material, which is sanitary. Furthermore, it is possible to eliminate the trouble of preparing a microwave shielding device separate from the bag.

Note that when using semiconductor oscillation instead of a magnetron as a microwave generation means, the oscillation frequency can be controlled, so for example, by arranging multiple patches with different resonant frequencies, the oscillation frequency can be controlled and the resonating patch can be changed depending on the purpose. By doing so, it becomes possible to further control the distribution.

In the embodiments described so far, the method of reducing the reflection phase is mainly composed of three layers: a conductive member with a large area, a dielectric material, and a second conductive member with a narrow area arranged periodically. Although an example of a planar patch resonator is shown, the present invention is not limited to this. It is also possible to realize a method of reducing the reflection phase by devising materials, such as mixing a conductive member with a dielectric, using a plurality of different dielectrics, or using a semiconductor. Further, instead of using a planar shape, a method of reducing the reflection phase may be realized by devising a shape such as using grooves, protrusions, or holes. Furthermore, a method of reducing the reflection phase may be realized using a mechanical, electrical, or chemical switching method such as changing the impedance by shorting or opening a conductive member.

As described above, the microwave shielding device of the present invention can block microwaves from reaching at least a part of the object to be processed (the part that is not desired to be processed) in the processing chamber so that the processing cannot proceed. Selective processing (selective heating in a microwave oven) or local processing (local heating in a microwave oven) can be performed. This fact can be effectively utilized in microwave processing equipment that performs heat treatment of food (or dielectric materials other than food), chemical reaction treatment, and the like.

1,48 Microwave oven (microwave processing device)
2, 26, 49 Processing chamber 9, 56 First food (material to be heat treated)
10, 39, 57 Second food (material to be treated that does not want to be heat treated)
11, 35, 58 Microwave shielding device 14, 15, 18, 40, 41, 42, 43, 51 Microwave 20, 36 First conductive member (conductive member with a wide area)
22, 37 Second conductive member (narrow area patch)
23, 38 Insulator (dish)
29 Planar patch resonator

Claims (15)

In microwave processing equipment that processes objects to be processed in a processing chamber by irradiating them with microwaves,
A microwave shielding device disposed within the processing chamber, with a side having a smaller reflection phase facing at least a portion of the object to be processed. 2. The microwave shielding device according to claim 1, wherein the front side and the back side have different reflection phases, and the back side having a smaller reflection phase is disposed facing the object to be processed. 3. The microwave shielding device according to claim 2, wherein the object to be processed has a region to be processed and a region not to be processed, and the back side of the object having a small reflection phase is placed facing the region to be processed. A claim in which there are a plurality of objects to be processed, a first object to be processed and a second object to be processed not to be processed, and arranged with the back side having a small reflection phase facing the second object to be processed. 3. The microwave shielding device according to 3. A microwave processing device is a microwave oven that heats an object by irradiating it with microwaves, and the object to be processed is food, and it separates a first food to be heat-treated and a second food not to be heat-processed. 5. The microwave shielding device according to claim 4, wherein heating of the second food is suppressed by arranging the back side having a small reflection phase toward the second food. 6. The microwave shielding device according to claim 1, having a conductive member having a reflection phase of approximately 180 degrees on the front side and a resonant member having a reflection phase of approximately 0 degrees on the rear side. 7. The resonant member is a planar patch resonator, and is configured to resonate by having a front conductive member having a large area and a second conductive member having a narrow area facing from the back side. Microwave shielding device as described. 8. The microwave shielding device according to claim 7, wherein the length of the second conductive member in at least one direction is an integral multiple of 1/2 of the effective length of the microwave. 8. The microwave shielding device according to claim 7, wherein the front conductive member and the second conductive member are covered with an insulator so as not to be exposed. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a plate. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a container. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a lunch box. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a lid. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a wrap. 10. The microwave shielding device according to claim 9, wherein the insulator also serves as a bag.