JP3671630B2 - Microwave cavity - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave cavity applied to a high-frequency heating apparatus that dielectrically heats an object to be heated using microwave energy, and more particularly to a microwave cavity that promotes uniform heating of an object to be heated. is there.
[0002]
[Prior art]
In a conventional microwave cavity of this type, as means for achieving uniform heating of the object to be heated contained in the cavity, a radio wave stirring method, a heated object rotation method, a multiple power supply method, or an uneven wall surface cavity is used. is there.
[0003]
The radio wave agitation method has a configuration in which a metallic plate-shaped blade provided in a microwave cavity is rotationally driven. In this system, microwaves propagating while being repeatedly reflected on the metal boundary surface forming the cavity and the surface of the object to be heated are also reflected by the metallic plate-like blades. The reflection of microwaves from the metal plate blades increases the microwave propagation path in the cavity compared to the case without plate blades, and diffuses the microwaves to the entire object to be heated. This promotes uniform heating of the object to be heated.
[0004]
The heated object rotation method is configured to rotationally drive a placing plate on which the heated object is placed. In this method, the object to be heated is moved relative to the microwave propagation distribution generated in the microwave cavity determined by the cavity structure and the type and shape of the object to be heated. It is propagated to promote uniform heating of the object to be heated.
[0005]
The multiple power feeding method is configured to feed microwaves into a cavity from a plurality of locations on a metal interface forming a microwave cavity. In this system, the greatest feature compared to a single power supply is that a plurality of microwaves having different phases are supplied into the cavity. By propagating microwaves having different phases in the cavity, a state of irregular reflection of the microwaves is generated in the cavity in the same manner as in the radio wave stirring method.
[0006]
The concavo-convex shape wall surface cavity structure system has a configuration in which concavo-convex portions are provided on a metal boundary surface forming a microwave cavity. In this system, microwaves are diffusely reflected by a metal interface having irregularities.
[0007]
[Problems to be solved by the invention]
However, the conventional microwave stirring type microwave cavity has a physical limit to uniformly diffuse the microwave reflected by the metal plate blades into the cavity. This is because the rotational speed of the metal plate blades is too slow relative to the propagation speed of the microwave, and even if the rotation speed of the metal plate blades is controlled, the entire object to be heated is uniformly microscopic. It is very difficult to propagate waves. Therefore, depending on the type and amount of the object to be heated, it has been difficult to suppress the occurrence of unexpected and uneven heating distribution.
[0008]
Also, in the heated object rotation method, the electromagnetic field distribution generated in the microwave cavity is naturally determined by the type and amount of the heated object, so the electromagnetic field distribution generated corresponding to one heated object is the heated object. However, the electromagnetic wave distribution cannot be changed even if it is unsuitable for uniformly heating.
[0009]
In the multiple power feeding method, the ideal behavior is as described above, but the behavior of the microwaves radiated from one power feeding unit is affected by the microwaves radiated from the other power feeding units. For this reason, even if there are a plurality of power feeding units, specific microwave propagation determined by the plurality of power feeding configurations occurs in the microwave cavity, so depending on the type and amount of the object to be heated, unexpected and uneven It was difficult to suppress the occurrence of heating distribution.
[0010]
Furthermore, the cavity structure of the concavo-convex-shaped wall surface is provided with irregularities such as so-called golf ball dimples on the entire wall surface to cause irregular reflection in the cavity that can promote uniform heating of the object to be heated. It is necessary to make the depth dimension or the projecting dimension non-negligible with respect to the microwave wavelength, for example, 1/10 wavelength dimension or more. As a result, the configuration of the microwave cavity is complicated, and there is a problem that a configuration that is difficult for practical use is forced.
[0011]
The present invention provides a microwave cavity for accelerating uniform heating of an object to be heated by variably controlling an electromagnetic wave distribution generated in a microwave space in a microwave cavity applied to a high-frequency heating apparatus.
[0012]
[Means for Solving the Problems]
The microwave cavity of the present invention substantially confines the fed microwave to solve the above problems. Consists of a roughly hexahedron Microwave space, Provided on at least one side of the rectangular hexahedron An opening and the opening To the outside of the microwave space, and a groove portion with a closed end, and a dielectric material fixedly disposed in the groove portion. And an impedance converter.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The invention also claims 1 and 2 The microwave cavity includes a microwave space composed of a substantially rectangular hexahedron that substantially confines the supplied microwave, an opening provided on at least one surface of the rectangular hexahedron, and the microwave space from the opening to the microwave space. A groove portion having a closed end extending outwardly, and the groove portion Fixed distribution Setting Shi The Made of dielectric material And an impedance converter. And the opening part is arrange | positioned so that the flow of the high frequency current produced in the metal wall surface which comprises a rectangular parallelepiped may be interrupted.
[0014]
The groove portion is configured to substantially confine the microwave so that high-frequency current can flow through the groove portion. Microwaves enter the groove part from the opening part, propagate through the inside, reflect at the end of the groove part, and propagate again to the microwave space from the opening part. The impedance conversion part provided in the groove part generates a prescribed impedance in the opening part, and regulates the propagation of the microwave incident on the opening part into the groove part. Then, the reflection characteristic of the microwave incident on the opening is changed to the reflection characteristic of the microwave generated by entering other than the opening. By providing this impedance converter, Without moving the impedance converter, Multiple propagation of microwaves or various electromagnetic field distributions can be generated in the microwave space.
[0015]
Furthermore, the present invention claims 3 The microwave cavity includes a microwave space for containing the object to be heated and substantially confining the supplied microwave, and a first wall surface that forms the microwave space and includes a microwave feeding unit, A second wall surface that forms the microwave space and does not include the first wall surface; an opening portion disposed in the second wall surface through a substantially central portion of the wall surface; and the opening portion A groove extending from the microwave space to the outside of the microwave space and closed in the groove Fixed distribution Setting Shi The Made of dielectric material And an impedance converter.
[0016]
And since the opening part is not arrange | positioned in the 1st wall surface which has a feed part, the microwave radiated | emitted from a feed part is radiated | emitted to microwave space, without producing disturbance in the radiation characteristic. Microwaves radiated to the microwave space are affected by the provision of the impedance converter described above, Without moving the impedance converter, Multiple propagation of microwaves or various electromagnetic field distributions can be generated in the microwave space to promote uniform heating of the entire object to be heated.
[0017]
The invention also claims 4 In the microwave cavity, the depth to the end of the groove is larger than a quarter of the wavelength of the microwave fed to the microwave space, and the arrangement position of the impedance converter from the opening is The dimensional configuration is less than ¼ wavelength of the wavelength of the microwave fed to the microwave space.
[0018]
And the microwave feed characteristic into microwave space changes with variable control of an impedance conversion part. By disposing the impedance conversion unit at the above position, it is possible to suppress a change in the power supply characteristic of the microwave to the microwave space and maintain a high power supply efficiency.
[0019]
The invention also claims 5 In the microwave cavity, the second wall surface has a plurality of wall surfaces, and the arrangement directions of the opening portions arranged on the respective wall surfaces are different.
[0020]
The object to be heated can be more effectively and uniformly heated by the multiple propagation of the microwaves reflected from the plurality of wall surfaces.
[0021]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0022]
(Example 1)
FIG. 1 is a configuration diagram of a high-frequency heating apparatus having a microwave cavity showing Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional configuration diagram of a main part of FIG.
[0023]
1 and 2, the microwave cavity 10 is a substantially rectangular parallelepiped made up of a right side wall surface 11, a left side wall surface 12, a back wall surface 13, an upper wall surface 14, a bottom wall surface 15 and a front wall surface 16 which are metal boundary portions made of a metal material. A microwave space 17 is formed which is configured in shape and substantially confines the fed microwave. Reference numeral 18 denotes an opening formed in the left wall 12, which is disposed at a substantially central portion in the vertical direction of the left wall 12 and has a substantially rectangular hole shape. On the outside of the microwave space 17 on the left wall surface 12, a groove plate 19 (a component of impedance conversion means) made of a metal material is assembled so as to cover the opening 18. The groove plate 19 forms a groove 20 having a predetermined groove depth L1 and a gap dimension L3 substantially equal to the opening dimension L2 of the opening 18. The opening 18 is disposed at one end of the groove 20, and the terminal end 21 of the groove is closed by the groove plate 19. Further, an impedance converter 22 (one component of impedance converter) is provided in the groove 20. The impedance converter 22 is made of a metal material and has a corrugated sliding dimension L4 that slides between the inner wall of the groove plate 19 and the left wall surface 12. Reference numeral 23 denotes a sliding shaft for sliding the impedance converter 22, and extends outside the groove 20 through the terminal end 21 of the groove. One end of the sliding shaft 23 is fixed to the impedance converter 22, and the other end is provided with a moving means (not shown) for moving the sliding shaft in a direction indicated by 24 in FIG. 2.
[0024]
The movable range of the impedance converter 22 has a minimum dimension L5 from the aperture and a maximum dimension (L1-L4).
[0025]
The right wall surface 11 is provided with a power feeding portion 25 that feeds microwaves to the microwave space 17, and the power feeding portion 25 is configured by an opening in the right wall surface 11 and a thin plate made of a low dielectric loss material that closes the opening. Has been. A placing plate 26 is provided in the approximate center of the bottom wall surface 15 to place an object to be heated and rotationally driven.
[0026]
Reference numeral 27 denotes an open / close door for taking a heated object into and out of the microwave space 17. A front wall surface 16 made of a mesh-like metal plate is provided at the center of the open / close door 27 so that the inside of the microwave space 17 can be seen through, and a heat-resistant glass plate 28 is disposed on the front surface from the microwave space 17 side of the front wall surface 16. It is attached to the wall 16. Reference numeral 29 denotes a hinge portion that supports opening and closing of the open / close door 27, and 30 denotes a door latch switch portion for detecting that the open / close door 27 is in a closed state. Reference numeral 31 denotes an operation unit for inputting microwave heating conditions of the object to be heated.
[0027]
Further, as a typical operation of the microwave on the left wall surface 12, in FIG. 2, a high-frequency current 32 that flows through the left wall surface 12, a microwave 33 incident on the metal surface, its reflected wave 34, and the opening 18 are shown. A microwave 35 incident thereon and its reflected wave 36 and transmitted wave 37 are shown.
[0028]
Next, the operation and action of the high-frequency heating apparatus provided with the microwave cavity of the present invention having the above configuration will be described.
[0029]
After placing an object to be heated on the mounting tray 26 and closing the open / close door 27, the apparatus starts operation by inputting a heating condition corresponding to the object to be heated from the operation unit 31. The microwave generated by the microwave generating means (not shown) at the start of the operation is radiated from the power supply unit 25 into the microwave space 17. The microwave propagating in the microwave space 17 is repeatedly reflected on each wall surface forming the microwave space 17 to form an electromagnetic field distribution in the microwave space. During this time, the microwave incident on the object to be heated dielectrically heats the object to be heated.
[0030]
A high-frequency current corresponding to the above-described electromagnetic field distribution flows on each wall surface forming the microwave space 17. Due to the presence of the opening 18, the high-frequency current 32 flowing through the left wall surface 12 is divided, and a microwave 37 propagating into the groove 20 is generated.
[0031]
The microwave 37 propagated in the groove 20 is reflected by the impedance converter 22 and propagates again in the microwave space 17 through the opening 18. A specific impedance is generated in the opening 18 by the propagation action of the microwave reflected from the inside of the groove 20 and propagating to the opening 18. Ideally, all values can be formed as impedance values generated in the opening portion 18, and restrictions on this value will be described later.
[0032]
The impedance of the aperture 18 can be changed by sliding the impedance converter 22. The opening 18 is provided so as to divide the flow of the high-frequency current 32. However, if the impedance of the opening 18 is made zero, the flow of the high-frequency current 32 is not divided. On the other hand, when the impedance of the opening 18 is infinite, the high frequency current 32 does not flow at all. The phase difference between the incident wave 35 and the reflected wave 36 of the microwave incident on the opening 18 is 180 degrees when the impedance of the opening 18 is zero, and the impedance of the opening 18 is infinite. In this case, it is 0 degree. Since the phase difference between the incident wave 33 and the reflected wave 34 of the microwave incident on the wall surface other than the opening 18 is 180 degrees, it can be obtained by reflection from the metal wall by changing the impedance of the opening. A microwave having a phase difference that cannot be propagated in the microwave space 17. Further, the electromagnetic field distribution generated in the microwave space 17 can be changed. As described above, the microwaves can be propagated in the microwave space 17 in a multiple manner to form various electromagnetic wave distributions, and the uniform heating of the entire object to be heated can be promoted.
[0033]
(Example 2)
FIG. 3 is a configuration diagram of a main part of a microwave cavity showing Embodiment 2 of the present invention. 3 is different from FIG. 2 in the configuration of the impedance converter 38.
[0034]
The impedance converter 38 is disposed at a distance L6 from the opening 18. The impedance converter 38 is configured to be rotatable in the groove 39, and has an effective relative dielectric constant of approximately 50 or more in the frequency band of a metal plate or a propagating microwave having a width smaller than the height L7 of the groove. It is composed of a plate made of a dielectric material exhibiting a value.
[0035]
As specific configuration dimensions for realizing the second embodiment, for example, the depth dimension L8 from the opening portion 18 of the terminal end 40 of the groove portion 39 is larger than ¼ of the wavelength of the microwave propagating through the groove portion 39. The distance dimension L6 to the rotation center of the impedance conversion part 38 made of a certain metal plate is 30 mm, which is approximately a quarter wavelength of the wavelength of the microwave propagating through the groove part 39, and the height dimension L7 of the groove part 39 is 15 mm. The width dimension of the conversion part 38 is 12 mm, and the thickness dimension is 3 mm. According to such a configuration dimension, compact mounting to a high-frequency heating device can be achieved.
[0036]
In such a rotationally driven impedance conversion unit 38, the impedance conversion unit 38 reflects most of the propagated microwave by setting the rotation position to the position indicated by the solid line 38a in FIG. On the other hand, the microwave is propagated to the end 40 of the groove 39 by setting the position indicated by the broken line 38b in FIG. The impedance generated in the opening 18 is changed by changing the microwave propagation in the groove 39 accompanying the rotational drive of the impedance converter 38.
[0037]
In addition, according to the configuration of the impedance conversion unit 38 that is rotationally driven, the impedance change that can be caused in the opening 18 even when continuously rotated is periodic, and the impedance value to be changed is set to a predetermined value. It can be limited. By this effect, it is possible to limit the multiple propagation of the microwave or the electromagnetic field distribution in the microwave space, and it is possible to control the generation of the multiple propagation or the electromagnetic field distribution corresponding to the uniform heating of the object to be heated.
[0038]
When the impedance converter 38 is made of a dielectric material, the microwave is reflected and transmitted on the layer surface of the impedance converter 38. By using a material having an effective relative dielectric constant of about 50 or more, the energy of the reflected wave with respect to the incident wave can be made 50% or more. Thereby, the reflection useful for impedance formation at the opening 18 can be reflected from the impedance converter made of the dielectric material.
[0039]
(Example 3)
FIG. 4 is a main part configuration diagram of a microwave cavity showing Embodiment 3 of the present invention. In FIG. 4, the difference from the above embodiment is that the impedance converting portion 41 is made of a dielectric material and fixedly arranged at a predetermined position L9 of the groove portion 42.
[0040]
The effective relative permittivity of the dielectric material constituting the impedance converter 41 is a value of about 4 or more and 7 or less in the frequency band of the microwave propagating through the groove 42. By using such an impedance converter 41, the microwave 43 that has propagated in the groove 42 is separated into a reflected wave 44 and a transmitted wave on the layer surface of the impedance converter 41. Of the transmitted wave, the transmitted wave 45 transmitted through the impedance converter 41 propagates to the end 46 of the groove 42, and the reflected wave 47 reflected by the end 46 is incident on the impedance converter 41 again. Of the reflected wave 47, the microwave 48 and the reflected wave 44 that have passed through the impedance converter 41 propagate to the opening 18 side. The microwave reflected to the opening 18 side determines the impedance value of the opening 18.
[0041]
It should be noted that the behavior of the reflection and transmission of the microwave at the impedance conversion unit 41 described above also occurs inside the impedance conversion unit 41, and it is refused that the microwave reflected to the opening 18 side exists in addition to the above. Keep it.
[0042]
Due to the action of the impedance converter 41 made of such a dielectric material, multiple propagation of microwaves can be generated inside the groove 42. Due to the occurrence of this multiple propagation, it is possible to cause multiple propagation of microwaves or various electromagnetic field distributions in the microwave space without moving the impedance converter.
[0043]
(Example 4)
FIG. 5 is a configuration diagram of a microwave cavity showing Embodiment 4 of the present invention. In FIG. 5, a right wall surface 49, a left wall surface 50, a bottom wall surface 51, a back wall surface 52, and an upper wall surface 53 are metal wall surfaces that form a microwave space 54.
[0044]
The right wall surface 49 (first wall surface) is provided with a power feeding portion 55, and a waveguide 56 for transmitting a microwave to be fed to the outside of the microwave space 54 is disposed. Reference numeral 57 denotes a coupling hole provided at one end of the waveguide 56, and an output antenna of microwave generating means (not shown) is inserted into and attached to the coupling hole 57.
[0045]
On the other hand, the left wall surface 50 that is the second wall surface and the back wall surface 52 that is the other second wall surface that face the right wall surface 49 that is the first wall surface are substantially passed through the substantially central portion of each wall surface. Opening portions 58 and 59 having a rectangular hole shape are formed. Further, groove plates 62 and 63 for forming predetermined groove portions 60 and 61 are disposed outside the microwave space 54 of the opening portions 58 and 59, respectively. Further, the impedance converters 64 and 65 shown in the third embodiment are disposed inside the grooves 60 and 61. Further, the opening portions 58 and 59 are arranged in different directions, the opening portion 58 is formed in the horizontal direction, and the opening portion 59 is formed in the vertical direction. Reference numeral 66 denotes a drive shaft that rotationally drives a mounting tray on which an object to be heated is mounted.
[0046]
And by the structure which has arrange | positioned the opening part 58 in the left side wall surface 50 which opposes the right side wall surface 49 which has the electric power feeding part 55, a to-be-heated material can be made to exist between an electric power feeding part and an opening part, and it injects directly. Uniform heating of the object to be heated can be promoted by causing the microwave and the microwaves that are multiple-reflected from the wall surface having the opening to enter the object to be heated.
[0047]
In addition, by arranging the openings in different orientations on the plurality of wall surfaces, it becomes possible for any of the openings to divide the high-frequency current with respect to various high-frequency current flows. . The object to be heated can be more effectively and uniformly heated by the multiple propagation of the microwaves reflected from the plurality of wall surfaces.
[0048]
Although the embodiment of the present invention has been described above, the operation of the impedance conversion section will be described below in more detail with reference to FIGS. 6 to 10 using the impedance conversion section shown in the first embodiment.
[0049]
FIG. 6 is a configuration diagram of a microwave cavity used for explaining the microwave action of the impedance converter of the present invention.
[0050]
In FIG. 6, 67 is a microwave cavity, 68 is a waveguide for transmitting microwaves to be fed to the microwave cavity 67, and 69 is opposed to a wall surface 70 in which the microwave cavity 67 is formed and provided with a feeding portion. It is a groove provided in the wall surface 71. The waveguide 68 is provided with a coupling hole 72 for mounting a magnetron as a microwave generating means. Further, nine microwave sensors are arranged on the metal wall surface 73 forming the microwave cavity 67 in an array of 3 rows and 3 columns as shown in the figure. This microwave sensor detects a physical quantity proportional to the intensity of the electromagnetic field distribution in the vicinity where the microwave sensor is disposed in combination with the electromagnetic field distribution generated in the microwave cavity 67.
[0051]
The microwave cavity 67 has a width dimension W, a depth dimension D, and a height dimension of 190 mm, 158 mm, and 100 mm, respectively. The groove 69 has a configuration in which a position of a depth L from an opening 74 (opening size 5 mm) passing through a substantially central portion of the metal wall surface 71 is closed by a metal plate 75. The metal plate 75 is configured to be slidable in the groove 69.
[0052]
With the depth L of the groove 69 set to 0 mm, the electromagnetic field distribution generated in the microwave cavity 67 is such that the number of standing wave peaks generated in the width direction, depth direction, and height direction is 2, 2, 0, respectively. I confirmed that there was. Accordingly, the aperture 74 arranged as shown is arranged so as to divide the high-frequency current against the occurrence of the standing wave.
[0053]
Then, the depth L of the groove 69 was changed, and the behavior of the microwave generated in the microwave cavity 67 was analyzed based on the detection signals of the nine microwave sensors. The sensor output signal of the microwave sensor is microwave power, but in the following description, a DC voltage value that has undergone signal conversion processing through a detection diode is used. Further, in order to distinguish the microwave sensor signal, the number as shown in the figure is given to the arrangement position.
[0054]
7 and 8 are characteristic diagrams showing the influence of the depth of the groove on the load characteristics of the microwave generating means. FIG. 7 is a characteristic example in a state where load matching between the microwave generating means and the microwave cavity 67 is not performed, and FIG. 8 is a characteristic example when the load matching is achieved.
[0055]
As shown in FIG. 7, by changing the depth L of the groove, the load characteristic of the microwave generating means shows a circular characteristic in the Smith chart. The load characteristics of the microwave generating means change periodically with respect to changes in the depth L of the groove. From this, it is recognized that the microwave supplied to the microwave space 67 propagates into the groove 69 through the opening 74.
[0056]
In addition, the load characteristics greatly change with respect to the change of the depth L before and after the depth L of the groove 69 is approximately ¼ wavelength (about 32.5 mm) of the propagation wavelength of the microwave. This is because the impedance generated in the aperture 74 changes greatly. Further, it can be seen that the groove 69 has the same function as the impedance matching means for adjusting the impedance matching state between the microwave cavity and the microwave generating means.
[0057]
An example of characteristics when an impedance matching member (not shown) is disposed in the waveguide 68 in order to realize load matching with the microwave generating means for the microwave cavity 67 including the load. As shown in FIG. The load matching was performed when the depth L of the groove 69 was 0 mm. By providing the impedance matching means in the waveguide 68, the power supply efficiency, which is the ratio at which the microwave generated by the microwave generation means can be supplied into the microwave cavity 67, is greatly improved compared to the characteristics of FIG. However, when the depth L is around 25 mm, the power supply efficiency is almost equivalent. In addition, when a microwave cavity exhibiting such load characteristics is applied to a high-frequency heating device, it is recognized that the frequency of the microwave generated by the microwave generating means can be changed by varying the depth L.
[0058]
Next, using a microwave cavity having the characteristics shown in FIG. 8, the influence of the depth L of the groove on the electromagnetic field distribution in the microwave cavity was examined. For this evaluation, a signal detected by the microwave sensor was used. An example of the evaluation result is shown in FIG.
[0059]
In FIG. 9, the depth dimension L is set to 0 mm, and the wavelength of the microwave used by the depth dimension L is approximately 1/8 wavelength (15.5 mm in the test example) and approximately 1/4 wavelength (test In the case of 31.5 mm in the example, the relative value with respect to each reference is shown.
[0060]
When the depth dimension L is approximately 1/8 wavelength, it is almost the same as the electromagnetic field distribution generated when the depth dimension L is 0 mm, but when the depth dimension L is approximately 1/4 wavelength, the electromagnetic field distribution is Obviously, there is a change. In addition, since the place where the electromagnetic field strength is strong in the case of about 1/8 wavelength is weak in the case of about 1/4 wavelength, the combination of these depth dimensions shows an electromagnetic field distribution close to mutual complement in the microwave cavity. It is recognized that
[0061]
Next, FIG. 10 shows an example of the temporal change of the electromagnetic field generated in the microwave cavity when the depth dimension of the groove is changed during the microwave power feeding.
[0062]
FIG. 10 shows that when the depth dimension L is set to approximately ¼ wavelength, the distribution of the electromagnetic field generated in the microwave cavity is made uniform.
[0063]
The present invention has been developed as a practical configuration that can be applied to a high-frequency heating apparatus by changing the microwave behavior in the microwave cavity by changing the depth dimension from the opening of the groove.
[0064]
As a practical configuration, the dimensions of the end of the groove and the aperture are slightly longer than a quarter wavelength of the microwave wavelength, and the impedance conversion unit has an arrangement dimension from the aperture of a quarter wavelength. The dimensions are short. As a result, the aperture has both capacitive and inductive impedances to promote multiple propagation of microwaves.
[0065]
【The invention's effect】
As described above, the present invention has the following effects.
[0066]
Claim 1 and According to the microwave cavity 2, the groove portion that extends from the opening portion to the outside of the microwave space is closed, and the groove portion Fixed distribution Setting Shi The Made of dielectric material By providing the impedance conversion unit, it is possible to form a predetermined impedance in the aperture using the microwave incident on the groove. As a result, Without moving the impedance converter, Multiple propagation of microwaves or various electromagnetic field distributions can be easily generated in the microwave space.
[0067]
According to the microwave cavity of the third aspect, the microwave radiated from the power feeding part is radiated into the microwave space without causing a disturbance in the radiation characteristic by providing the opening in the wall surface without the power feeding part. Can be made. And Without moving the impedance converter, By the microwave action of the opening portion, multiple propagation of microwaves or various electromagnetic field distributions can be generated in the microwave space, and uniform heating of the entire object to be heated can be promoted.
[0068]
Claim 4 According to the microwave cavity of the present invention, by setting the depth dimension to the end of the groove and the arrangement position of the impedance converter from the aperture, the microwave space can be controlled against the variable impedance of the aperture. It is possible to suppress the change in the power supply characteristics of the microwaves and maintain high power supply efficiency.
[0069]
Claim 5 According to the microwave cavity, any one of the apertures can divide the high-frequency current by providing the power supply unit on a plurality of wall surfaces and changing the arrangement direction of the apertures arranged on each wall surface. Thus, it is possible to provide a microwave cavity that can cope with various electromagnetic field distributions and to heat the object to be heated more effectively and uniformly by the multiple propagation of the microwaves reflected from the plurality of wall surfaces.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a high-frequency heating apparatus to which a microwave cavity showing Example 1 of the present invention is applied.
[Fig. 2] Configuration of the main part of the microwave cavity
FIG. 3 is a configuration diagram of a main part of a microwave cavity showing a second embodiment of the present invention.
FIG. 4 is a main part configuration diagram of a microwave cavity showing Embodiment 3 of the present invention.
FIG. 5 is a configuration diagram of a microwave cavity showing a fourth embodiment of the present invention.
FIG. 6 is a configuration diagram of a microwave cavity for explaining the microwave action according to the present invention.
FIG. 7 is a first characteristic diagram showing the influence of the depth of the groove provided in the opening according to the present invention on the load matching of the microwave generating means.
FIG. 8 is a second characteristic diagram showing the influence of the depth of the groove provided in the opening according to the present invention on the load matching of the microwave generating means.
FIG. 9 is a characteristic diagram showing the influence of the depth of the groove provided in the opening according to the present invention on the electromagnetic field distribution in the microwave cavity.
FIG. 10 is a characteristic diagram showing an example of the temporal change that the variation of the depth of the groove provided in the opening according to the present invention gives to the electromagnetic field distribution in the microwave cavity.
[Explanation of symbols]
10,67 microwave cavity
17,54 microwave space
18, 58, 59, 74 Opening
20, 39, 42, 60, 61, 69 Groove (impedance conversion means)
21, 40, 46, 75 Termination of groove (impedance conversion means)
22 Impedance converter (impedance converter)
25,55 Power feeding unit
32 high frequency current
38 Rotation driven impedance converter
41, 64, 65 Impedance converter made of non-metallic material
49,70 The first wall surface having the power feeding part
50, 52, 71 Second wall surface with opening
L1, L8, L Depth from opening to end of groove
L5, L6, L9 Distance dimension from the opening to the impedance converter

Claims (5)

A microwave space composed of a substantially rectangular hexahedron that substantially confines the supplied microwave, an opening provided on at least one surface of the rectangular hexahedron, and a termination extending from the opening to the outside of the microwave space microwave cavity with the the groove closed, and said consists of a fixed arrangement with a dielectric material in the groove impedance converter. Opening the microwave cavity according to claim 1, wherein disposed so as to divide the flow of high-frequency current generated in the metal wall constituting a rectangular hexahedron. A microwave space for containing an object to be heated and substantially confining a microwave supplied thereto, a first wall surface forming the microwave space and having a microwave feeding portion, and forming the microwave space In addition, a second wall surface not including the first wall surface, an opening portion disposed through the substantially central portion of the wall surface in the second wall surface, and the microwave space from the opening portion. microwave cavity with a groove end extending outwardly is closed, and an impedance conversion unit consisting of a fixed arrangement with dielectric material in said groove. The depth to the end of the groove portion is larger than a quarter wavelength of the wavelength of the microwave fed to the microwave space, and the arrangement position from the opening portion of the impedance converter is fed to the microwave space. The microwave cavity according to claim 1 or 3 , wherein the microwave cavity has a dimensional configuration of less than a quarter wavelength of the wavelength of the microwave. A microwave space for containing an object to be heated and substantially confining a microwave supplied thereto, a first wall surface forming the microwave space and having a microwave feeding portion, and forming the microwave space In addition, a second wall surface not including the first wall surface, an opening portion disposed through the substantially central portion of the wall surface in the second wall surface, and the microwave space from the opening portion. A groove portion having a closed end extending outward, and an impedance conversion portion provided in the groove portion, wherein the second wall surface has a plurality of wall surfaces, and an opening portion disposed on each wall surface. A microwave cavity with a different arrangement direction.

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