High-frequency heating equipment

Abstract

To provide a radio frequency heating apparatus in which high-frequency power is propagated from a transmission body to a radiating portion by surface waves, and the entire heated object is heated by the high-frequency waves radiated from the radiating portion.SOLUTION: A radio frequency heating apparatus according to the present disclosure includes a high-frequency power generation portion that generates high-frequency power, a transmission body that propagates the high-frequency power as a surface wave, and a radiating portion installed in the transmission body and radiating a surface wave in the transmission body as a high frequency to heat an object to be heated.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a radio frequency heating device in which surface waves are propagated. [Background technology]

[0002] Patent Document 1 discloses a high-frequency heating device in which a surface wave transmission line is disposed above an object to be heated. This high-frequency heating device includes a heating chamber, a waveguide, a radio wave transmitter, an object-to-be-heated mounting table, and a stub-type surface wave transmission line. The heating chamber is provided with a plurality of protrusions for fixing the mounting table, the height of which can be changed, so that the distance between the object to be heated and the surface wave transmission line can be adjusted according to the height of the object to be heated.

[0003] Figure 1 shows a schematic diagram of a conventional rotating antenna power supply system. An object to be heated 2 is placed on a mounting table 3 inside a heating chamber 1 surrounded by metal walls and heated. High-frequency power is radiated into the heating chamber 1 from a high-frequency power generator 4 such as a magnetron via a waveguide 5, a rotating antenna axis 6, and a horizontal antenna part 7.

[0004] Figure 2 shows an explanatory diagram of high-frequency power propagation in a conventional rotating antenna power supply system. As shown in Figure 2(a), high-frequency power propagates through an electric field 8 between the horizontal antenna part 7 and the metal wall surface of the heating chamber 1, and is radiated from the tip of the horizontal antenna part 7. The conventional rotating antenna power supply system achieves the suppression of uneven heating with such a simple structure. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 51-142141 Summary of the Invention [Problem to be solved by the invention]

[0006] However, since many foods are thick, even if the surface can be heated by Patent Document 1, there is a limit to how evenly the entire food can be heated. Figure 2(b) shows the distribution of the electric field 8 perpendicular to the propagation direction at the horizontal antenna section 7 of the conventional rotating antenna power supply system. Because the horizontal antenna section 7 is far from the metal wall of the heating chamber 1, the electric field 8 spreads laterally, causing radiation in a direction different from the propagation direction, resulting in high-frequency power leakage. Such high-frequency power radiation from near the rotating antenna axis 6 hardly moves even when the antenna rotates, resulting in uneven heating. Furthermore, high-frequency power leakage during propagation reduces the radiated power from the rotating and moving antenna tip, reducing the effectiveness of suppressing uneven heating.

[0007] The present disclosure provides a high-frequency heating device in which high-frequency power is propagated from a transmitter to a radiator by surface waves, and the entire object to be heated is heated by the high-frequency waves radiated from the radiator. [Means for solving the problem]

[0008] In order to solve the above conventional problems, The high frequency heating device of the present disclosure comprises a mounting table on which the object to be heated is placed, a high frequency power generating unit that generates high frequency power, a transmitter that propagates the high frequency power as a surface wave, and a radiation unit that is installed on the transmitter and radiates the surface waves in the transmitter as high frequency waves to heat the object to be heated.This allows microwaves to be supplied to the radiation unit using a leak-proof surface wave line, and microwaves to be radiated only from the position within the heating chamber that is optimal for heating food, so that a wide variety of objects to be heated can be heated to the desired state. [Effects of the Invention]

[0009] The high-frequency heating device according to the present disclosure can radiate high-frequency waves from the radiation unit, which are propagated from a transmitter using a surface wave line with low leakage. As a result, the high-frequency waves radiated from the optimal position for heating food can heat the food while suppressing uneven heating overall. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of a conventional rotating antenna power supply system [Figure 2] (a) Explains the propagation of high-frequency power using a conventional rotating antenna power feed system. (b) Explains the distribution of high-frequency power in the orthogonal direction using a conventional rotating antenna power feed system. [Figure 3] 1 is a schematic diagram of a high-frequency heating device according to a first embodiment of the present invention; [Figure 4] Schematic diagram of the transmitter of the high-frequency heating device [Figure 5] Illustrative diagram of high-frequency current and electric field distribution in a stub [Figure 6] An explanatory diagram showing the length of a radiation portion in a part of a transmitter. [Figure 7] Schematic diagram of a high-frequency heating device according to a second embodiment of the present invention. [Figure 8] Schematic diagram of a high-frequency heating device according to a third embodiment of the present invention. [Figure 9] 10 is a schematic diagram of a high-frequency heating device according to a fourth embodiment of the present invention, in which the mounting table and the transmitter are close to each other. [Figure 10] Illustrative diagram of the heating effect near the object to be heated in the state of Figure 9 [Figure 11] FIG. 10 is a schematic diagram of a high-frequency heating device according to a fourth embodiment of the present invention when the mounting table and the transmitter are far apart. [Figure 12] Illustrative diagram of the heating effect near the object to be heated in the state of Figure 11 DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that formed the basis of this disclosure) At the time when the inventors came up with the idea for the present disclosure, the technology of heating an object by propagating high-frequency power as a surface wave was known as a technology that bakes the object.

[0012] Under these circumstances, the inventors came up with the idea of ​​using surface waves to not only bake but also warm an object to be heated.The inventors then discovered a problem in that, in order to heat an object to be heated, it is necessary to spread high-frequency power to places far from the surface wave transmission line that are difficult to heat, and in order to solve this problem, they came up with the subject matter of the present disclosure.

[0013] Furthermore, to prevent uneven heating of the object, it is desirable to radiate high-frequency power from multiple positions suitable for heating. However, it was discovered that with many conventional power supply methods, leakage during propagation causes radiation from unintended locations, reducing the effectiveness of preventing uneven heating.

[0014] Therefore, the present disclosure provides a high-frequency heating device comprising a mounting table on which an object to be heated is placed, a high-frequency power generating unit that generates high-frequency power, a transmission body that propagates the high-frequency power as a surface wave, and a radiation unit that is installed on the transmission body and radiates the surface wave in the transmission body as a high frequency wave, thereby heating the object to be heated.

[0015] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of well-known matters or redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0016] The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0017] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0018] [Overall configuration] Figure 3 shows a schematic diagram of the high-frequency heating apparatus according to the first embodiment of the present invention. An object to be heated 2 is placed on a mounting table 3 in a heating chamber 1 surrounded by metal walls and is heated. High-frequency power is supplied from a high-frequency power generating unit 4, such as a magnetron or semiconductor oscillator, to a radiating unit 11 via a transmitter 10. The radiating unit 11 is placed in a location intended to prevent uneven heating, and radiates high-frequency power into the heating chamber 1.

[0019] The high-frequency heating device of the present invention also includes a heating condition setting unit (not shown) that sets heating conditions, and a heating control unit (not shown) that heats the object to be heated based on the heating conditions set by the heating condition setting unit.

[0020] Incidentally, the radiation position may be moved by elevating or rotating the transmitter 10 and the radiation part 11, so that uneven heating can be further suppressed.

[0021] [Transmission body] Figure 4 shows an explanatory diagram of the transmitter of the same high-frequency heating device. The transmitter 10 is composed of a periodic structure part in which plate-shaped stubs 12 are periodically arranged, and a connecting part 13 that electrically and mechanically connects one end of the stubs 12. The radiating part 11 is connected to the connecting part 13 and acts as an antenna that radiates into space the high-frequency power that has propagated through the transmitter 10 as a surface wave.

[0022] Figure 5 shows an explanatory diagram of the distribution of high-frequency current and electric field in the stub. The transmitter 10 propagates high-frequency power in the form of a surface wave. Figure 5 shows the flow path of high-frequency current 9 at a given moment through stub 12 and coupling portion 13. High-frequency power in the form of a surface wave propagates by repeatedly generating high-frequency current 9 from the tip of stub 12 via coupling portion 13 to the tip of another stub 12. This flow path is approximately λ / 2, allowing high-frequency power to propagate efficiently in a resonant state. The electric field 8 is concentrated between the start and end points of the high-frequency current 9. Because the tips of the stubs 12 are close to each other, the electric field 8 does not spread into space but is concentrated near the tips of the stubs 12, suppressing radiation and leakage of high-frequency power and allowing efficient propagation.

[0023] In this way, by making the transmitter 10 a surface wave line, high frequency waves are concentrated and distributed in the vicinity of the periodic structure, which suppresses radiation leakage along the path and effectively suppresses uneven heating by the radiation section 11.

[0024] [Emission part] Radiation section 11, which is a monopole antenna, is connected to coupling section 13 of transmission body 10. High-frequency current 9 propagating in the form of a surface wave has a large current distribution at coupling section 13, which is approximately midway along its flow path, making it suitable for exciting the antenna.

[0025] In this way, by connecting the radiating portion 11 to the coupling portion 13 of the transmitting body 10, the flow of high frequency current into the antenna, that is, the radiating portion 11, can be increased, and high frequency power can be efficiently radiated from the tip of the antenna.

[0026] In this case, the radiation part 11 may be, for example, a plate-like, rod-like, cylindrical, rectangular parallelepiped, etc. as shown in FIGS. 4 and 5. It is sufficient that these have a length sufficient to determine the direction of radiation so that they can radiate high frequency power.

[0027] The radiating section 11 matches the impedance between the transmission path of the transmitter 10 and the space in the heating chamber 1. When matching the low impedance of the transmission path with the high impedance of the space, as shown in Figure 6, the radiating section 11, which is configured as a monopole antenna, can match at a length of approximately L = λ / 4 + λ / 2 × n, where L is the overall length, and can increase the radiation efficiency.

[0028] Furthermore, the radiating portion 11 has a portion on its tip side that is inclined relative to the transmitter 10. By inclining it so that it is away from the metal wall surface of the heating chamber 1 as shown in Figure 5, the impedance at the radiating portion 11 can be made to change continuously, and the radiation range on the terminal side can be expanded toward the heating chamber while maintaining matching. Here, in the first embodiment, the radiating portions 11 extend from both ends of the transmitter 10 as shown in Figure 3, and both are inclined toward the load side space.

[0029] As described above, in the first embodiment, the length L of the radiating section 11 is λ / 4 + λ / 2 * n, where n is an integer including 0. By using a transmission line with dimensions equal to λ / 4 multiplied by an integer including 0, the transmission line functions as a λ / 4 impedance transformer. By adjusting the impedance at the point where the transmission line is coupled and the impedance as seen from the radiating end to a range of approximately ±λ / 12, the transmitter 10 and the space within the heating chamber 1 can be more precisely matched. This suppresses reflections between the transmitter 10, the radiating section 11, and the space within the heating chamber 1, optimizes the match, and maximizes the high-frequency radiation into the heating chamber 1. Optimizing the match minimizes reflections from the end and maximizes the high-frequency radiation into the heating chamber.

[0030] (Embodiment 2) Hereinafter, the second embodiment will be described with reference to FIG.

[0031] [Rotation drive mechanism] FIG. 7 shows a schematic diagram of the high-frequency heating device of the second embodiment. A rotary drive mechanism 14, such as a motor, can rotate the transmitter 10 and the radiation unit 11 around the power supply position from the high-frequency power generation unit 4 to the transmitter 10. By rotating the transmitter 10 and the radiation unit 11, the radiation position of the high-frequency power moves, making it possible to heat the object to be heated while suppressing uneven heating overall. With this configuration, not only can the transmitter 10 and the radiation unit 11 simply rotate, but the tilted direction of the radiation unit 11 can also be moved or changed to an optimal position depending on the placement of the object to be heated, thereby heating the object.

[0032] As a method of implementing this rotation drive mechanism, for example, when the object to be heated 2 is placed on the mounting table 3 and a menu is selected using the heating condition setting unit, the heating control unit controls the heating according to the selected menu. The installation orientation of the radiation unit 11, whether or not to rotate, and the speed are set according to the menu and the type and size of the object to be heated. This rotation moves the radiation position and the object to be heated, allowing the object to be heated evenly.

[0033] In this way, by changing the positional relationship between the radiation position by the rotary drive mechanism and the object to be heated, uneven heating can be suppressed.

[0034] In this embodiment, the configuration in which the transmitter 10 and the radiation part 11 are rotationally driven has been described, but the mounting table 3 on which the object to be heated 2 is placed may also be rotationally driven.

[0035] (Embodiment 3) Hereinafter, the third embodiment will be described with reference to FIG.

[0036] [Lifting drive mechanism] FIG. 8 shows a schematic diagram of the high-frequency heating device of the third embodiment. The table 3 on which the object 2 to be heated is placed can be raised and lowered by an elevation drive mechanism 15 using a motor or the like. Rotating the radiation position of the high-frequency power is effective in suppressing uneven heating in the plane, but since the radiation position does not change in the vertical direction, it is less effective in suppressing uneven heating up and down. By raising and lowering the table 3 on which the object 2 to be heated is placed, the radiation position and the vertical position of the object 2 to be heated change, allowing the object to be heated with reduced uneven heating up and down.

[0037] As a method of implementing this lifting drive mechanism, for example, when an object to be heated is placed on the mounting table 3 and a menu is selected using the heating condition setting unit or the like, the heating control unit controls heating according to the selected menu. With this configuration, heating or baking is set according to the menu and the type and size of the object to be heated, the lifting position is determined, and the distance between the transmitter 10 and the upper surface of the mounting table 3 or the object to be heated 2 is set. This lifting may be set to switch between multiple positions at different time intervals when heating one object to be heated.

[0038] As shown in Figure 8, for example, if the distance between the transmitter 10 and the object to be heated 2 is M, the distance M can be adjusted using the heating condition setting unit and the heating control unit to switch between partial baking and total heating of the object to be heated.

[0039] The switching between baking and heating is performed using a selection menu in the heating condition setting unit to set conditions suitable for each object to be heated. Specifically, the heating control unit heats the object to be baked under the heating conditions set by the heating condition setting unit, with the distance M between the transmitter 10 and the object 2 being equal to or less than a predetermined distance. When the object to be heated is entirely heated, the heating control unit heats the object to be heated under the conditions set by the heating condition setting unit, with the distance M between the transmitter 10 and the object 2 being equal to or greater than a predetermined distance.

[0040] When the distance M between the transmitter 10 and the object 2 to be heated is reduced to a predetermined distance or less, the electric field concentrated near the tip of the stub 12 can partially bake the object to be heated.

[0041] If the distance M between the transmitter 10 and the object to be heated 2 is set to a predetermined distance or more, a surface wave line with no leakage can be used, and microwaves can be supplied to the radiation section 11, and microwaves can be radiated only from the position within the heating chamber 1 that is optimal for heating the entire food, so that a wide variety of objects can be heated to the desired state.

[0042] In this way, by using the lifting drive mechanism to adjust the distance M between the transmission unit and the object to be heated, the heating state of the object to be heated can be selected, as explained above.

[0043] In this embodiment, the configuration has been described in which the table 3 on which the object to be heated 2 is placed is driven to move up and down, but the transmitter 10 and the radiation part 11 may also be driven to move up and down.

[0044] (Fourth embodiment) The fourth embodiment will be described below with reference to FIGS.

[0045] [When the mounting table and the surface wave transmitter are close to each other] Figure 9 is a schematic diagram of a high-frequency heating device having a lifting drive mechanism 15 in an embodiment, in which the mounting table 3 is in a lowered state and the distance M between the transmission body 10 and the object to be heated 2 is close.

[0046] FIG. 10 is a diagram of the vicinity of the object 2 to be heated in FIG. 9, and is an explanatory diagram of the heating effect when the transmitter 10 and the object 2 to be heated are close to each other. For example, the distance M1 is set to 5 mm. Note that 5 mm corresponds to approximately λ / 24 at 2.45 GHz. The electric field 8 of the transmitted surface wave reaches the tip of the stub 12. The electric field 8 is concentrated in the vicinity, suppressing radiation and leakage of high-frequency power and allowing for efficient propagation. Therefore, if the object to be heated 2 is intentionally brought close to the tip of the stub 12 as shown in Figure 10, the electric field 8 concentrated near the tip of the stub 12 penetrates into the object to be heated 2 and heats it. In such a case, the object to be heated 2 is heated strongly and baked, so browning can be achieved near the tip of the stub 12. The high-frequency energy supplied to the radiation part 11 is reduced, and the overall heating of the object to be heated 2 by radiation is weakened.

[0047] Next, we will explain the specific value of the distance M. The electric field value and its range of the surface waves generated near the surface wave line vary slightly depending on the surface wave line method, the concentration design, the frequency and power of the propagating high frequency, etc., but from the results of experiments heating several types of food using surface waves, it was found that the range of distance M at which food burns is about 5 mm at a household power of 500 W. Furthermore, the range of distance M at which the surface wave power directly penetrates the heated object and partially heats the food is about 10 mm at a household power of 500 W. In other words, by controlling the distance between the transmitter 10 and the heated object 2 to 5 mm or less, or between 5 mm and 10 mm, it is possible to selectively use partial browning heating or partial heating without burning.

[0048] [When the mounting table and the surface wave transmitter are far apart] Figure 11 is a schematic diagram of a high-frequency heating device having a lifting drive mechanism 15 in an embodiment, in which the mounting table 3 is in an elevated state and the distance M between the transmission body 10 and the object to be heated 2 is increased.

[0049] Figure 12 shows the vicinity of the object 2 in Figure 11 and explains the heating effect when the transmitter 10 and the object 2 are spaced apart. For example, assume the distance M2 = 15 mm. Note that 15 mm corresponds to approximately λ / 8 at 2.45 GHz. The electric field 8 of the transmitted surface wave is concentrated near the tip of the stub 12, suppressing the radiation and leakage of high-frequency power and enabling efficient propagation. When the tip of the stub 12 and the object 2 are spaced apart as shown in Figure 12, the electric field 8 is concentrated near the tip of the stub 12, but it does not penetrate the object 2, resulting in almost no heating effect. Therefore, the microwave can be transmitted to the radiation unit 11 without power loss. In this case, the radiation unit 11 can radiate microwaves only from the optimal position on the object 2, enabling the desired overall heating process for a wide variety of objects. In this case, the overall heating of the object 2 due to radiation is strong.

[0050] Next, we will explain the specific value of the distance M. The electric field value and its range of the surface waves generated near the surface wave line vary slightly depending on the surface wave line method, the concentration design, the frequency and power of the propagating high-frequency waves, etc., but from the results of experiments heating several types of food using surface waves, it was found that the range of the distance M within which food is partially heated at 500W for domestic use is about 10mm. In other words, by setting the distance M between the transmitter 10 and the object to be heated 2 to 15mm or more, taking into consideration various conditions such as the surface wave line method, the concentration design, the frequency and power of the propagating high-frequency waves, it is possible to prevent the surface wave power from being directly absorbed by the object to be heated during propagation, and to achieve overall heating with reduced uneven heating.

[0051] In this way, it is possible to selectively control overall heating with reduced uneven heating, partial browning heating, and partial heating without burning by increasing or decreasing the distance between the transmitter 10 and the heated object 2. In other words, by controlling the distance between the transmitter 10 and the heated object 2 to 15 mm or more, 5 mm or less, or between 5 mm and 10 mm, it is possible to selectively control overall heating with reduced uneven heating, partial browning heating, and partial heating without burning.

[0052] Therefore, in this embodiment, the predetermined distance is preferably 5 mm (λ / 24) or more and 15 mm (λ / 8) or less.

[0053] Note that baking, full heating, and partial heating vary depending on the type of object being heated and personal preferences, so the distance M for baking is not limited to M = 5 mm. Similarly, the distance M for full heating is not limited to M = 15 mm.

[0054] In addition, the distance at which the food is considered to burn or heat is the distance from the bottom surface of the heated object to the transmitter 10, and in this embodiment, this is set as the distance from the top surface of the mounting table 3, which is in contact with the bottom surface of the heated object 2, to the transmitter 10.

[0055] (Other embodiments) Furthermore, since the degree of concentration of the electric field 8 near the tip of the stub 12 is related to the frequency of the propagating high-frequency power, it is possible to control the frequency to selectively use either overall heating that suppresses uneven heating or partial browning heating.

[0056] Since such a method is possible, the predetermined distance does not necessarily have to be set to 5 mm or more and 15 mm or less, and the setting can be changed appropriately depending on the individual high-frequency heating device and the object to be heated.

[0057] In addition, to control the distance between the transmitter 10 and the mounting table 3 or the object to be heated 2, in addition to the means for moving the mounting table 3 up and down as in this embodiment, there is also a means for moving the transmitter 10 itself up and down within the heating chamber 1, for example.

[0058] Note that, for example, if the object to be heated 2 is placed in a container such as a dish and there is a distance between the table 3 and the object to be heated, the predetermined distance may not be in the range of 5 mm to 15 mm. In such a case, the predetermined distance may be adjusted as appropriate so that the object to be heated 2 is heated to the desired state.

[0059] In addition, in the above case, in order to set the predetermined distance, the user may, for example, input an indication that a container is present, or the position of the heated object 2 may be detected by a heated object detection means such as an optical sensor.

[0060] Furthermore, although the transmission body 10 is described as being composed of a periodic structure portion in which plate-like stubs 12 are periodically arranged and a coupling portion 13 that electrically and mechanically connects one end of the stubs 12, it may take a different form. For example, the surface wave transmission line may have a generally flat structure having a periodic structure, and the periodic structure may be a ladder type, a meander type, or an interdigital type. Using a generally flat structure not only makes it possible to make the device more compact, but also makes it easier to rotate and drive it up and down.

[0061] (effect) As described above, in this embodiment, the high-frequency heating device comprises a mounting table 3, a transmitter 10, and a radiation unit 11, and the object to be heated 2 is mounted on the mounting table 3. The transmitter 10 propagates high-frequency power as a surface wave. The radiation unit 11 is attached to the transmitter 10 and radiates high-frequency waves to heat the object to be heated. This allows microwaves to be supplied to the radiation unit using a leak-free surface wave line, and microwaves can be radiated only from the optimal position within the heating chamber for heating the food, making it possible to heat a wide variety of objects to the desired state.

[0062] As in this embodiment, the high-frequency heating device may have a predetermined distance or more between the transmitter 10 and the upper surface of the table 3 or the object to be heated 2. This allows microwaves to be supplied to the radiation unit using a leak-free surface wave line, and microwaves can be radiated only from the optimum position for heating food within the heating chamber, making it possible to heat a wide variety of objects to the desired state.

[0063] As in the present embodiment, the high-frequency heating device may have a predetermined distance or less between the transmitter 10 and the upper surface of the mounting table 3 or the object 2 to be heated. This allows the object to be partially baked by surface waves.

[0064] As in this embodiment, the high-frequency heating device may be provided with a heating condition setting unit and a heating control unit, which allow the distance between the transmitter 10 and the upper surface of the mounting table 3 or the object 2 to be heated to be adjusted by the heating condition setting unit and the heating control unit, thereby switching between baking the object to be heated and heating the entire object.

[0065] As in this embodiment, the high-frequency heating device may have a predetermined distance of 5 mm or more and 15 mm or less, which allows for more accurate switching between baking the object to be heated and partial heating and overall heating.

[0066] As in this embodiment, the high-frequency heating device may have a predetermined distance of λ / 24 or more and λ / 8 or less, which allows for more accurate switching between baking the object to be heated and partial heating and full heating.

[0067] As in this embodiment, the tip of the radiation part of the high-frequency heating device may be inclined with respect to the transmitter. This widens the radiation side of the radiation part, allowing it to be coupled to a large space, improving radiation efficiency.

[0068] As in this embodiment, in the high-frequency heating device, the inclined portion of the tip of the radiation part may be inclined toward the load-side space (upper side), which widens the radiation range of the radiation part toward the heating chamber side and increases the high-frequency power directed toward the object to be heated.

[0069] As in this embodiment, the direction of the inclined portion of the tip of the radiation unit of the high-frequency heating device may be changeable depending on the placement of the object to be heated. This allows radiation to be emitted from the optimal position on the object to be heated, and a wide variety of objects can be heated in the desired state.

[0070] As in this embodiment, the length of the radiation section of the high-frequency heating device may be λ / 4+λ / 2*n, which makes the impedance on the radiation side of the radiation section closer to the impedance of the heating chamber space, reducing reflection and improving radiation efficiency.

[0071] As in this embodiment, the high-frequency heating device may be adjusted so that the impedance of the radiating part matches the spatial impedance of the radiation destination. This reduces reflection at the radiating part and improves radiation efficiency.

[0072] As in the present embodiment, the high frequency heating device may have a mechanism for rotating the transmission body, which makes it possible to heat the object to be heated while suppressing uneven heating across the entire area.

[0073] As in this embodiment, the high-frequency heating device may have a mechanism for raising and lowering the transmitter. This allows the object to be heated while suppressing uneven heating overall. In addition, it is possible to switch between baking the object and heating the entire object.

[0074] As in this embodiment, the high-frequency heating device may change the frequency of the high-frequency power generated by the high-frequency power generator, thereby controlling the concentration of surface waves on the transmitter, changing the heated area and the strength of the distributed electric field, and controlling the baking strength of the heated object.

[0075] As in this embodiment, the high-frequency heating device may use the radiation part to match the transmitter with the space inside the heating chamber 1. This can suppress reflection at the radiation part, improving radiation efficiency into the heating chamber. [Industrial Applicability]

[0076] As described above, the present disclosure can heat an object to be heated while suppressing uneven heating overall with a simple structure, and therefore can be applied to cooking appliances such as microwave heaters. [Explanation of symbols]

[0077] 1 Heating chamber 2 Object to be heated 3. Mounting table 4. High frequency power generation section 5 Waveguide 6 Rotating antenna axis 7 Antenna horizontal section 8 Electric Field 9 High frequency current 10 Transmission Body 11 Radiation section 12 Stub 13 Connecting part 14 Rotation drive mechanism 15 Lifting drive mechanism

Claims

1. a mounting table on which an object to be heated is placed; a high frequency power generating unit that generates high frequency power; a transmitter that propagates the high-frequency power as a surface wave; a radiation unit that is installed in the transmitter and radiates the surface wave in the transmitter as a high frequency wave to heat the object to be heated; Equipped with When the distance between the upper surface of the mounting table or the object to be heated and the transmitter is equal to or greater than a predetermined distance, the object to be heated is entirely heated by the high frequency waves radiated from the radiation unit, When the distance between the upper surface of the mounting table or the object to be heated and the transmitter is equal to or shorter than a predetermined distance, at least a portion of the object to be heated is baked by the surface waves. High frequency heating device.

2. A mounting table on which an object to be heated is placed; a high frequency power generating unit that generates high frequency power; a transmitter that propagates the high-frequency power as a surface wave; a radiation unit that is installed in the transmitter and radiates the surface wave in the transmitter as a high frequency wave to heat the object to be heated; a heating condition setting unit that sets heating conditions; a heating control unit that heats the object to be heated based on the heating conditions set by the heating condition setting unit, The heating control unit heats the object to be heated with a distance between the transmitter and the object being a predetermined distance or less when baking the object to be heated, and heats the object to be heated with a distance between the transmitter and the object being a predetermined distance or more when warming the object to be heated, according to the heating conditions set by the heating condition setting unit. High frequency heating device.

3. The predetermined distance is equal to or greater than 5 mm and equal to or less than 15 mm. The high frequency heating device according to claim 1 or 2.

4. the predetermined distance is equal to or greater than 1 / 24 wavelength and equal to or less than 1 / 8 wavelength; The high frequency heating device according to claim 1 or 2.

5. The tip of the radiating portion has a portion inclined with respect to the transmitting body. The high frequency heating device according to any one of claims 1 to 4.

6. The inclined portion is inclined toward the load side space (upper side). The high frequency heating device according to claim 5 .

7. The orientation of the inclined portion can be changed depending on the placement of the object to be heated. The high frequency heating device according to claim 5 or 6.

8. The length of the radiation portion is 1 / 4 wavelength + 1 / 2 wavelength * n. The high frequency heating device according to any one of claims 1 to 7.

9. When the radiation unit radiates high frequency waves to heat the object to be heated, the impedance of the radiation unit is adjusted to match the spatial impedance of the radiation destination. The high frequency heating device according to any one of claims 1 to 8.

10. The transmission body has a mechanism for rotating. The high frequency heating device according to any one of claims 1 to 9.

11. The transmitter has a mechanism for raising and lowering. The high frequency heating device according to any one of claims 1 to 10.

12. The frequency of the high frequency power generated by the high frequency power generation unit is changed to change the heating range of the surface wave in the transmitter. The high frequency heating device according to any one of claims 1 to 11.

13. a heating chamber for accommodating the object to be heated; The radiation portion suppresses reflection of high frequencies between the transmitter and the space in the heating chamber, Matching the impedance of the transmission body with the space within the heating chamber; The high frequency heating device according to any one of claims 1 to 12.

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