High-frequency heating device

Abstract

The high-frequency heating device of the present disclosure includes a heating chamber, a surface wave line, an oscillation source, a waveguide, a power supply shaft, a power supply line, and a coupling point. The surface wave line is disposed in the heating chamber. The oscillation source oscillates high-frequency power. The waveguide transmits the high-frequency power from the oscillation source. The power supply shaft transmits the high-frequency power transmitted by the waveguide to the heating chamber. The power supply line transmits the high-frequency power transmitted by the power supply shaft to the surface wave line. The coupling point electrically connects the power supply line and the surface wave line. The distance from the end portion closest to the coupling point among the multiple end portions of the resonant current flow path provided in the surface wave line to the coupling point is set to the wavelength of the resonant current × (1 / 4 + 1 / 2 × integer value ± 1 / 8).

Description

Technical Field

[0001] This invention relates to a high-frequency heating device that uses surface wave circuitry to heat an object. Background Technology

[0002] Patent Document 1 discloses a high-frequency heater, the purpose of which is to uniformly and efficiently heat a surface wave circuit or a heated object by configuring it to move freely. The high-frequency heater described in Patent Document 1 includes a surface wave circuit, an electromagnetic oscillator, a conductive component, and a rotating device.

[0003] The surface wave circuit excites high-frequency electricity to induce a surface wave mode within the heating chamber. An electromagnetic oscillator oscillates this electromagnetic energy. A waveguide, coupled to the oscillator, has an opening in the wall of the heating chamber. Conductive components protrude through the opening into the waveguide and are fixed to a portion of the surface wave circuit. A rotating device rotates the object being heated or the surface wave circuit.

[0004] In this disclosure, the high-frequency electric current of the surface wave attitude will be referred to as a surface wave, and heating based on the surface wave will be referred to as surface wave heating.

[0005] Patent Document 2 discloses a high-frequency heating device that automatically adjusts the output power of an oscillation source to supply maximum power to the food regardless of the amount of food. The high-frequency heating device described in Patent Document 2 includes an oscillation source, a surface wave exciter, a heating chamber, a waveguide, a dielectric, an adjustment device, a drive device, a cutting section, a detector, and a control section.

[0006] An oscillator source oscillates high-frequency electricity. A surface wave exciter converts the high-frequency electricity into a surface wave state, propagating the high-frequency electricity in this state to heat the food. A heating chamber holds the food to be heated. A waveguide directs the high-frequency electricity into the heating chamber. Food is placed on a dielectric substrate.

[0007] An adjustment device is disposed within the waveguide to adjust the impedance to supply maximum power to the food. A drive device moves the adjustment device. A cutoff unit cuts off leakage current from the adjustment device and the drive device. A detector detects the maximum power supply to the food based on high-frequency noise, etc. A control unit controls the oscillation source, the adjustment device, and the drive device.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 52-155442

[0011] Patent Document 2: Japanese Patent Application Publication No. 6-338387 Summary of the Invention

[0012] This disclosure provides a high-frequency heating device that can maximize surface wave heating.

[0013] The high-frequency heating device disclosed herein includes a heating chamber, a surface wave circuit, an oscillation source, a waveguide, a power supply shaft, a power supply line, and a coupling point.

[0014] The surface wave circuit is located within the heating chamber. An oscillator oscillates high-frequency electricity. A waveguide transmits the high-frequency electricity from the oscillator. A power supply shaft transmits the high-frequency electricity from the waveguide to the heating chamber. A power supply line transmits the high-frequency electricity from the power supply shaft to the surface wave circuit. A coupling point electrically connects the power supply line and the surface wave circuit.

[0015] The distance from the end closest to the coupling point among the multiple ends of the resonant current path set in the surface wave circuit to the coupling point is set to (1 / 4 wavelength + an integer multiple of 1 / 2 wavelength) ± 1 / 8 wavelength, that is, the wavelength of the resonant current × (1 / 4 + 1 / 2 × integer value ± 1 / 8).

[0016] The high-frequency heating device of the present invention can supply power to a surface wave circuit under appropriate conditions. This optimizes impedance matching at the coupling point and suppresses unwanted high-frequency power radiation and reflection. As a result, surface wave heating can be maximized. Attached Figure Description

[0017] Figure 1 This is a schematic structural diagram of the high-frequency heating device according to Embodiment 1 of this disclosure.

[0018] Figure 2 This is a schematic diagram illustrating the operation of the surface wave circuit in the high-frequency heating device of Embodiment 1.

[0019] Figure 3 This is an enlarged schematic diagram of the surface wave circuit and power supply unit of the high-frequency heating device in Embodiment 1.

[0020] Figure 4 This is an enlarged schematic diagram of the surface wave circuit and power supply unit of the high-frequency heating device in Embodiment 1.

[0021] Figure 5A This is a diagram illustrating the structure of the electromagnetic field analysis model in the high-frequency heating device of Embodiment 1.

[0022] Figure 5B yes Figure 5A A sectional view of the main parts.

[0023] Figure 6A It means in Figure 5AThe figure shows the electromagnetic field analysis results when the distance Lf is fixed at a specified value and the distance Hf is varied in the electromagnetic field analysis model shown.

[0024] Figure 6B It means in Figure 5A The figure shows the electromagnetic field analysis results when the distance Hf is fixed at a specified value and the distance Lf is varied in the electromagnetic field analysis model shown.

[0025] Figure 7 This is a schematic structural diagram of the surface wave circuit and power supply unit of the high-frequency heating device according to Embodiment 2 of this disclosure. Detailed Implementation

[0026] (The views, etc., that form the basis of this disclosure)

[0027] At the time of this disclosure, the inventors believed that surface wave heating using surface wave circuits was known as one of the techniques for grilling heated objects.

[0028] According to the prior art described in Patent Document 1, it is difficult to achieve impedance matching at the fixed location when only a conductor component is fixed in a part of the surface wave circuit and protrudes into the waveguide. Therefore, the reflection and radiation of high-frequency power at the fixed part increases, and sometimes the conversion efficiency to surface wave mode decreases.

[0029] The high-frequency heating device described in Patent Document 2 is intended to provide the maximum power from the high-frequency electricity oscillating from the oscillation source to the food. However, according to the prior art described in Patent Document 2, even if the impedance mismatch in the waveguide can be improved by adjusting the device, high-frequency electricity radiation may sometimes occur at the point of impedance discontinuity in the transmission of high-frequency electricity from the waveguide to the surface wave line, thus failing to maximize surface wave heating.

[0030] The inventors of this application have studied the maximization of surface wave heating based on surface wave circuits in a structure used to rotate surface wave circuits and suppress uneven heating of the heated object.

[0031] Power supply methods for surface wave circuits can be based on electric field coupling, magnetic field coupling, and current coupling. In the cases of electric field coupling and magnetic field coupling, the surface wave circuit and the power supply unit are non-contact. Therefore, the device structure becomes complex, leading to larger overall device size and increased manufacturing costs.

[0032] In the case of current coupling, the surface wave circuit is directly connected to the power supply. Therefore, without impedance matching at the connection point, the reflection and radiation of high-frequency electric current increase at the connection point between the conductor component protruding into the waveguide and the surface wave circuit. Consequently, the high-frequency electric current converted to a surface wave mode decreases.

[0033] To address these issues, it is necessary to balance the rotation of the surface wave circuit used to suppress uneven heating of the heated object with maximizing the heating of the heated object based on the surface wave circuit. Therefore, the inventors of this application conceived of using a simple power supply structure to optimize the impedance matching at the connection point between the surface wave circuit and the power supply device, thus completing the subject matter of this disclosure.

[0034] According to the high-frequency heating device of the present invention, surface wave heating can be maximized by optimizing the position of the coupling point between the surface wave line and the power supply line and the length of the power supply path.

[0035] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, for example, detailed descriptions of known matters and repeated descriptions of the same or substantially the same structures may be omitted at times.

[0036] (Implementation Method 1)

[0037] The following uses Figures 1-6B The high-frequency heating apparatus 100 of Embodiment 1 of this disclosure will be described.

[0038] Figure 1 This is a schematic structural diagram of the high-frequency heating device 100. Figure 1 As shown, the high-frequency heating device 100 includes a heating chamber 1, a mounting platform 3, an oscillation source 4, a waveguide 5, a power supply shaft 6, a power supply line 7, a coupling point 8, and a surface wave line 9.

[0039] The heating chamber 1 is sealed by a metal wall when its front surface opening is blocked by a door (not shown), and inside it is a roughly horizontally arranged mounting platform 3. The object to be heated 2 is placed on the mounting platform 3, which serves as a dielectric. The oscillation source 4 is a device that generates high-frequency electricity, such as a magnetron or a semiconductor oscillator. The waveguide 5 transmits the high-frequency electricity generated by the oscillation source 4 to the power supply shaft 6.

[0040] The power supply shaft 6 has a lower end 6a and an upper end 6b, and is a cylindrical shaft connecting the waveguide 5 and the heating chamber 1. The lower end 6a is disposed inside the waveguide 5. The upper end 6b is disposed inside the housing constituting the heating chamber 1 and below the mounting platform 3. The power supply line 7 is disposed inside the housing constituting the heating chamber 1 and below the mounting platform 3, and is connected to the upper end 6b of the power supply shaft 6.

[0041] High-frequency power is transmitted from the oscillator 4 to the power supply line 7 and the heating chamber 1 via the waveguide 5 and the power supply shaft 6. A coupling point 8 is located at the end of the power supply line 7. The power supply line 7 and the surface wave line 9 are connected at the coupling point 8. The power supply line 7 transmits high-frequency power from the power supply shaft 6 to the surface wave line 9 via the coupling point 8. In this embodiment, the waveguide 5, the power supply shaft 6, and the power supply line 7 constitute a power supply unit 20 that transmits high-frequency power from the oscillator 4 to the surface wave line 9.

[0042] The surface wave circuit 9 converts the high-frequency power received via the coupling point 8 into a surface wave attitude, and the high-frequency power of the surface wave attitude is transmitted in the surface wave circuit 9. The high-frequency power of this surface wave attitude heats the object 2 placed near the surface wave circuit 9, forming scorch marks on the object 2.

[0043] The surface wave circuit 9 is connected to the power supply shaft 6 via the power supply circuit 7. The power supply shaft 6 is connected to a motor (not shown) and rotates in conjunction with the rotation of the motor. That is, the power supply shaft 6 functions as a rotating shaft that supports the power supply circuit 7 and the surface wave circuit 9 for free rotation.

[0044] Figure 2 This is a schematic diagram illustrating the operation of the surface wave circuit 9 included in the high-frequency heating device 100 of this embodiment. For example... Figure 2 As shown, the surface wave line 9 has a periodic structure, which includes a plurality of short stubs 91 erected parallel to each other at fixed intervals on a base.

[0045] Multiple stubs 91 include stub 91a and stub 91b. Stub 91a is the stub closest to the power supply line 7 and connected to the power supply line 7 at coupling point 8. Stub 91b is a stub that is relatively close to the power supply line 7 and close to stub 91a. Figure 2 In the diagram, stub 91a is the first stub observed from power supply line 7, and stub 91b is the third stub observed from power supply line 7.

[0046] The surface wave line 9 converts the supplied high-frequency power into high-frequency power in a surface wave orientation. The surface wave line 9 transmits the high-frequency power in a surface wave orientation, i.e., the surface wave, in a direction perpendicular to the plurality of stubs 91. That is, the transmission direction of the surface wave is a radiation direction perpendicular to the power supply axis 6 and centered on the power supply axis 6.

[0047] Surface wave circuit 9 has proximity to mounting platform 3 (see reference) Figure 1 The end portion 9a and the end portion 9b of the stub 91a. End portion 9a is the end of the stub 91a closest to the mounting platform 3 (the upper end in this embodiment). End portion 9b is the end of the stub 91b closest to the mounting platform 3 (the upper end in this embodiment).

[0048] In the surface wave circuit 9 that excites the surface wave, the resonant current 10 flows through the flow path that connects the end portion 9a and the end portion 9b of the surface wave circuit 9 via short stubs 91a and 91b.

[0049] Hereinafter, the flow path through which the resonant current 10 flows will be referred to as the resonant current flow path 10a. The resonant current flow path 10a has a length approximately half the wavelength of the resonant current 10. Therefore, charge accumulates at the end portions 9a and 9b, generating an electric field 11. As a result, the object to be heated 2, which is positioned near the surface wave line 9, is heated.

[0050] In this disclosure, half the length of the wavelength of the resonant current 10 is referred to as half the wavelength. That is, the wavelength refers to the wavelength of the resonant current 10. Similarly, one-quarter of the length of the wavelength of the resonant current 10 is referred to as the one-quarter wavelength, and one-eighth of the length of the wavelength of the resonant current 10 is referred to as the one-eighth wavelength. The terms one-quarter wavelength and one-eighth wavelength will be described later.

[0051] In the resonant current path 10a, a magnetic field 12 is generated around the resonant current 10. Energy transfer occurs between the electric field 11 and the magnetic field 12 via the resonant current 10. Through this energy transfer, the electric field 11 and the magnetic field 12 resonate.

[0052] By setting the flow path length of the resonant current path 10a to approximately half a wavelength, the potential at the end portions 9a and 9b can be maximized. As a result, surface wave heating can be maximized. As described above, the stub 91b is positioned at a distance where the flow path length of the resonant current 10 is approximately half a wavelength.

[0053] In the surface wave circuit 9, it is preferable to have only one coupling point 8. If multiple coupling points are provided, the multiple high-frequency currents flowing into the surface wave circuit 9 from these points may interfere with each other, thus hindering the excitation of the current at each coupling point. Furthermore, avoiding this situation could complicate the construction of the device.

[0054] Figure 3 as well as Figure 4 This is an enlarged schematic diagram of the surface wave circuit 9 and the power supply unit 20 of the high-frequency heating device 100 of this embodiment. Figure 3 This indicates the case where distance L1 and distance L3 are the same. Figure 4 This indicates the case where distance L1 and distance L2 are the same. Distances L1 to L3 will be discussed later.

[0055] like Figure 3 as well as Figure 4As shown, the power supply line 7 is current-coupled at the coupling point 8, which is located midway through the resonant current path 10a in the surface wave line 9. Structurally, the power supply line 7 is connected to the surface wave line 9 in such a way that it protrudes from the side of the surface wave line 9 at the coupling point 8. In this embodiment, the power supply line 7 is connected in such a way that it abuts at approximately a right angle to the side of the stub 91a closest to the power supply line 7 among the plurality of stubs 91 included in the surface wave line 9.

[0056] When a high-frequency current flows into the side of the surface wave circuit 9 via the power supply line 7, a resonant current 10 is generated in the surface wave circuit 9 and propagates in the resonant current flow path 10a. Thus, the surface wave circuit 9 can excite surface waves.

[0057] Distance L1 is the length of the power supply path from the lower end 6a of the power supply shaft 6 through the upper end 6b of the power supply shaft 6 and the power supply line 7 to the coupling point 8. By adjusting distance L1, the impedance at the end of the power supply line 7, i.e., the impedance at the coupling point 8, can be adjusted.

[0058] Distance L2 is the length of the power supply path via the stub 91a between end 9a and coupling point 8. Distance L3 is the length of the power supply path via the stubs 91a and 91b between end 9b and coupling point 8. The impedance of the surface wave line 9 is maximum at end 9a and end 9b. The impedance at coupling point 8 is determined by distances L2 and L3.

[0059] A resonant current 10 is excited in the resonant current path 10a through current coupling. Therefore, in order to maximize the degree of current coupling, it is preferable to set the coupling point 8 at the position where the resonant current 10 in the resonant current path 10a is at its maximum. Specifically, it is preferable to set the coupling point 8 in the stub 91a at a position approximately 1 / 4 wavelength away from the end portion 9a.

[0060] However, the impedance of the power supply line 7, which is configured to be electrically floated relative to the heating chamber 1, is slightly higher due to the impedance of the space inside the heating chamber 1. Furthermore, in the case of a structure in which the surface wave line 9 is rotated by a motor, the impedance varies to some extent due to changes in parasitic capacitance with the surroundings.

[0061] Therefore, a balance needs to be struck between the degree of current coupling and impedance matching at the connection point. Specifically, the position of coupling point 8 needs to be slightly adjusted starting from a position approximately 1 / 4 wavelength away from the end portion 9a. Regarding the adjustment of the position of coupling point 8, from the perspective of impedance matching, the following methods are used... Figures 5A-6B To be described later.

[0062] exist Figure 3 and Figure 4In the case where the impedance matching at coupling point 8 is optimized and the surface wave is excited by the surface wave line 9, the sum of distances L1 and L2 or the sum of distances L1 and L3 is, in principle, an integer multiple of 1 / 2 wavelength.

[0063] In this state, for example, when the sum of distances L1 and L2 is an integer multiple of half a wavelength, such as Figure 3 As shown, distance L3 is approximately the same as distance L1. When the sum of distances L1 and L3 is an integer multiple of half the wavelength, as... Figure 4 As shown, the distance L2 is approximately the same as the distance L1.

[0064] Next, use Figure 5A , Figure 5B , Figure 6A , Figure 6B The allowable range of dimensions that can maintain impedance matching at coupling point 8 is explained.

[0065] Figure 5A This is a diagram illustrating the structure of the electromagnetic field analysis model in the high-frequency heating device 100 of this embodiment. Figure 5B yes Figure 5A The main part of the sectional view, specifically, is along... Figure 5A A cross-sectional view along line AA. Figure 6A and Figure 6B express Figure 5A The electromagnetic field analysis results are shown in the electromagnetic field analysis model.

[0066] in addition, Figure 5A , Figure 5B The orthogonal coordinate system, including the X, Y, and Z axes, is used to represent the orientation of the structural elements in the electromagnetic field analysis model of the high-frequency heating device 100. The origin of this orthogonal coordinate system is located at the intersection of the bottom of the shell constituting the heating chamber 1 and the centerline of the power supply axis 6.

[0067] The X-axis extends along the length of the waveguide 5 and the surface wave line 9. That is, the X-axis corresponds to the transverse direction of the high-frequency heating device 100. The high-frequency power supplied to the waveguide 5 propagates in the negative X-axis direction within the waveguide 5, and the high-frequency power of the surface wave propagates in the negative X-axis direction within the surface wave line 9.

[0068] The Y-axis extends along the shorter side of the waveguide 5 and the surface wave line 9. That is, the Y-axis corresponds to the depth direction of the high-frequency heating device 100. The XY plane is a horizontal plane. The Z-axis extends along the vertical direction, with the positive direction of the Z-axis being vertically upward.

[0069] exist Figure 5BIn this context, distance Lf is the length of the power supply path in power supply line 7 from the intersection of power supply line 7 and power supply shaft 6 to coupling point 8. Distance Hf is the length of the power supply path from coupling point 8 to the stub 91a at the end 9a.

[0070] Figure 6A This indicates the impedance matching result at coupling point 8 when the distance Lf is fixed at a specified value and the distance Hf is varied. Figure 6B This represents the impedance matching result at coupling point 8 when the distance Hf is fixed at a specified value while the distance Lf is varied. Figure 6A and Figure 6B In the diagram, the horizontal axis represents frequency, and the vertical axis represents the relative value (scattering parameter S11) with respect to the target value of impedance matching.

[0071] like Figure 5A As shown, the electromagnetic field analysis model of the high-frequency heating device 100 is... Figure 1 The high-frequency heating device 100 shown also includes a heating chamber 1, a waveguide 5, a power supply shaft 6, a power supply line 7, and a surface wave line 9. In this electromagnetic field analysis model, the end face of the waveguide 5 parallel to the YZ plane is set as the inlet port for electromagnetic field analysis.

[0072] Figure 6A and Figure 6B This represents the impedance matching result at coupling point 8 observed from the inlet port of waveguide 5, with distances Hf and Lf as varying factors. Using... Figure 6A as well as Figure 6B Find the range of distances Hf and Lf that can maintain the lower limit of the target value for impedance matching below -3dB.

[0073] exist Figure 6A In the analysis shown, the distance Lf was fixed at 8 mm while the distance Hf was varied from 5 mm to 20 mm. Under these conditions, the scattering parameter S11 could be maintained in the frequency range FR below -3 dB. Figure 6A The range of the horizontal arrow in the image is 0.057 GHz.

[0074] That is, when the distance Hf changes by 15 mm, the frequency change at coupling point 8 to achieve impedance matching is 0.057 GHz. Based on this analysis, the variation in distance Hf, which corresponds to the 0.1 GHz frequency bandwidth of the ISM band (Industrial Scientific and Medical Band) from 2.4 GHz to 2.5 GHz in the high-frequency heating device 100, is calculated. The result is that the variation is 26.2 mm.

[0075] exist Figure 6BIn the analysis shown, the distance Hf was fixed at 10 mm while the distance Lf was varied from 5 mm to 15 mm. Under these conditions, the frequency range FR (the range indicated by the horizontal arrow in the figure) that can maintain the scattering parameter S11 below -3 dB is 0.03 GHz.

[0076] That is, when the distance Lf changes by 10 mm, the frequency change at the coupling point 8 to achieve impedance matching is 0.03 GHz. Based on this analysis, the variation of distance Lf is calculated to be equivalent to the 0.1 GHz frequency bandwidth of the ISM band (2.4 GHz to 2.5 GHz) in the high-frequency heating device 100. The result is that the variation is 32.9 mm.

[0077] Based on the above results, the average amplitude of the variation in the ISM band is approximately 30 mm. This average amplitude corresponds to 1 / 4 wavelength. Therefore, the dimension used to maintain impedance matching at coupling point 8 is preferably set to the center value ± 1 / 8 wavelength. Furthermore, the specified values ​​for distance Hf and distance Lf mentioned above are examples and are not limited to these values.

[0078] As described above, by adjusting the length of the power supply path, which is determined by the position of coupling point 8, the size of power supply shaft 6, and the size of power supply line 7, the impedance matching at coupling point 8 can be optimized. That is, by slightly adjusting the position and setting each dimension to the intended value, the impedance matching at coupling point 8 can be optimized and maintained.

[0079] This simplifies the connection of the mechanical components required to rotate the surface wave circuit 9. As a result, surface wave heating can be maximized while suppressing uneven heating.

[0080] [Effects, etc.]

[0081] The high-frequency heating device 100 of this embodiment includes a heating chamber 1, a surface wave circuit 9, an oscillation source 4, a waveguide 5, a power supply shaft 6, a power supply line 7, and a coupling point 8.

[0082] Surface wave circuit 9 is configured in heating chamber 1. Oscillator 4 oscillates high-frequency electricity. Waveguide 5 transmits high-frequency electricity from oscillation source 4. Power supply shaft 6 transmits the high-frequency electricity from waveguide 5 to heating chamber 1. Power supply line 7 transmits the high-frequency electricity from power supply shaft 6 to surface wave circuit 9. Coupling point 8 electrically connects power supply line 7 and surface wave circuit 9.

[0083] The distance from the end 9a closest to the coupling point 8 among the multiple ends of the resonant current path 10a, which is the path of the resonant current 10 in the surface wave circuit 9, to the coupling point 8 is set to the wavelength of the resonant current 10 × (1 / 4 + 1 / 2 × integer value ± 1 / 8), that is, (1 / 4 wavelength + 1 / 2 wavelength multiple) ± 1 / 8 wavelength.

[0084] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0085] In the high-frequency heating device 100 of this embodiment, the coupling point 8 may also be located in the middle of the resonant current flow path 10a. The power supply line 7 may also be connected at the coupling point 8 in a direction protruding from the resonant current flow path 10a.

[0086] Therefore, surface wave attitude excitation can be reliably performed in the surface wave circuit 9, maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0087] In the high-frequency heating device 100 of this embodiment, the distance from the end (lower end 6a) of the waveguide 5 through the power supply shaft 6 and the power supply line 7 to the end closest to the coupling point can also be set to the wavelength of the resonant current 10 × (1 / 2 × integer value ± 1 / 8), that is, an integer multiple of 1 / 2 wavelength ± 1 / 8 wavelength.

[0088] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0089] In the high-frequency heating device 100 of this embodiment, the coupling point can also be set at the following position: at this position, the distance L1 from the end (lower end 6a) of the power supply shaft 6 located in the waveguide 5 to the coupling point 8 is the same as the distance L2 from the end portion 9a closest to the coupling point 8 at the end portion of the resonant current flow path 10a of the surface wave line 9 to the coupling point 8.

[0090] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0091] The high-frequency heating device 100 in this embodiment may also have a coupling point 8.

[0092] Therefore, surface wave attitude excitation can be reliably performed in the surface wave circuit 9, maximizing surface wave heating. Thus, various objects 2 can be heated to the desired state.

[0093] In the high-frequency heating device 100 of this embodiment, the power supply line 7 and the surface wave line 9 can also be electrically connected to the power supply shaft 6 and rotate freely about the power supply shaft 6 as the central axis.

[0094] Therefore, by utilizing a simple structure that allows the surface wave circuit 9 to rotate, uneven heating of the heated object 2 caused by surface waves can be suppressed. Thus, various heated objects 2 can be heated to the desired state.

[0095] In the high-frequency heating device 100 of this embodiment, the coupling point 8 may also be set at a position where the impedance of the end of the power supply line 7, which is determined by the distance L1 from the end (lower end 6a) of the power supply shaft 6 provided in the waveguide 5 to the end of the power supply line 7, is the same as the impedance determined by the distribution of the resonant current 10 in the middle of the resonant current flow path 10a.

[0096] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0097] (Implementation Method 2)

[0098] The following uses Figure 7 Implementation method 2 will be described. Figure 7 This is a schematic structural diagram of the surface wave circuit 9 and the power supply unit 20 included in the high-frequency heating device of this embodiment.

[0099] In Implementation 1, the length of the power supply path is adjusted, determined by the position of the coupling point 8, the size of the power supply shaft 6, and the size of the power supply line 7. This allows for a simple construction that optimizes both the rotation of the surface wave line 9 and the impedance matching at the coupling point 8.

[0100] However, according to Embodiment 1, when the surface wave line 9 is arranged above the power supply shaft 6, it is not possible to set the coupling point 8 in the middle of the surface wave line 9 with a periodic structure.

[0101] like Figure 7 As shown, the surface wave circuit 9 according to this embodiment has a cutout 13 located at the lower center of the stub 91a. A coupling point 8 is located at the cutout 13 of the stub 91a, and the power supply line 7 is connected to the stub 91a at the coupling point 8.

[0102] In this structure, distance L1 is the length of the power supply path from the lower end 6a of the power supply shaft 6 located in the waveguide 5 to the coupling point 8, that is, the sum of the length of the power supply shaft 6 and the length of the power supply line 7.

[0103] Distance L2 is the length of the power supply path from the end 9a closest to the coupling point 8 among the multiple ends of the resonant current flow path 10a to the coupling point 8 via the stub 91a, 91b. Distance L3 is the length of the power supply path from the coupling point 8 through the stubs 91a and 91b to the end 9b of the stub 91b. The size (height) of the cutout 13 is set by adjusting distances L1 to L3.

[0104] In particular, a cutout 13 is provided in the lower center of the stub 91a of the surface wave line 9, such that the distance L1 is an integer multiple of 1 / 4 wavelength + 1 / 2 wavelength ± 1 / 8 wavelength. The power supply line 7 is coupled to the stub 91a of the surface wave line 9 at the coupling point 8 provided in the cutout 13.

[0105] According to this structure, the impedance matching at the coupling point 8 can be optimized while the surface wave line 9 is excited to generate a surface wave, thereby maximizing the surface wave heating.

[0106] [Effects, etc.]

[0107] In the high-frequency heating device 100 of this embodiment, the surface wave circuit 9 is arranged on the central axis of the power supply shaft 6. The surface wave circuit 9 has a cutout 13 provided on the side of the power supply shaft 6. The coupling point 8 is provided in the cutout 13.

[0108] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0109] The high-frequency heating device 100 of this embodiment can also adjust the impedance at the coupling point 8 of the power supply line 7 according to the size of the cut portion 13.

[0110] This allows for optimal impedance matching between the power supply line 7 side and the surface wave line 9 side at coupling point 8, suppressing uneven heating and maximizing surface wave heating. As a result, various objects 2 can be heated to the desired state.

[0111] Industrial availability

[0112] This disclosure can be applied to high-frequency heating devices capable of performing surface wave heating.

[0113] Label Explanation

[0114] 1: Heating chamber; 2: Object to be heated; 3: Platform; 4: Oscillation source; 5: Waveguide; 6: Power supply shaft; 6a: Lower end; 6b: Upper end; 7: Power supply line; 8: Coupling point; 9: Surface wave line; 9a, 9b: End section; 10: Resonant current; 10a: Resonant current flow path; 11: Electric field; 12: Magnetic field; 13: Cut-out section; 20: Power supply section; 91, 91a, 91b: Short stubs; 100: High-frequency heating device.

Claims

1. A high-frequency heating device, wherein, The high-frequency heating device includes: Heating chamber; A surface wave circuit is disposed in the heating chamber; An oscillation source, which is configured to oscillate and generate high-frequency electricity; A waveguide configured to transmit the high-frequency power from the oscillation source; The power supply shaft is configured to transmit the high-frequency power transmitted from the waveguide to the heating chamber; The power supply line is configured to transmit the high-frequency power transmitted from the power supply shaft to the surface wave line; as well as A coupling point that electrically connects the power supply line to the surface wave line. The distance from the end closest to the coupling point among the multiple ends of the resonant current path that serves as the resonant current path in the surface wave circuit to the coupling point is set to the wavelength of the resonant current × (1 / 4 + 1 / 2 × integer value ± 1 / 8).

2. The high-frequency heating device according to claim 1, wherein, The coupling point is located in the middle of the resonant current flow path. The power supply line is connected at the coupling point in a direction protruding from the resonant current path.

3. The high-frequency heating device according to claim 1, wherein, The distance from the end of the power supply shaft located in the waveguide, through the power supply shaft and the power supply line, to the end closest to the coupling point is set as the wavelength of the resonant current × (1 / 2 × integer value ± 1 / 8).

4. The high-frequency heating device according to claim 1, wherein, The coupling point is set at a position where the distance from the end of the power supply shaft of the waveguide to the coupling point is the same as the distance from the end closest to the coupling point to the coupling point.

5. The high-frequency heating device according to claim 1 or 2, wherein, The high-frequency heating device has one of the coupling points.

6. The high-frequency heating device according to claim 1 or 2, wherein, The power supply line and the surface wave line are electrically connected to the power supply shaft and can rotate freely about the power supply shaft as the central axis.

7. The high-frequency heating device according to claim 1, wherein, The surface wave circuit is configured on the central axis of the power supply shaft. The surface wave circuit has a cutout located on the power supply shaft side. The coupling point is located at the cut.

8. The high-frequency heating device according to claim 7, wherein, The high-frequency heating device can adjust the impedance at the coupling point of the power supply line according to the size of the cut.

Images