High-frequency heating device

Abstract

A high-frequency heating device (100) according to the present disclosure comprises: a plurality of surface wave lines (8); an oscillation source (4); and a power supply unit (20) (a waveguide (5), a power supply shaft (6), and a power supply line (7)). The oscillation source (4) supplies high-frequency power. The power supply unit (20) transmits the high-frequency power from the oscillation source (4) to the plurality of surface wave lines (8). The plurality of surface wave lines (8) are distributed in a two-dimensional manner and are disposed so as to be mutually independent.

Description

High-frequency heating equipment

[0001] The present disclosure relates to a high-frequency heating device that heats an object to be heated using a surface wave line.

[0002] Patent Document 1 discloses a high-frequency heater that aims to uniformly and efficiently heat an object to be heated by configuring the surface wave line or the object to be heated to be freely movable. The high-frequency heater described in Patent Document 1 includes a radio wave oscillator, a surface wave line, a waveguide, a conductive member, and a rotating device.

[0003] The radio wave oscillator generates high frequency power. The surface wave line excites high frequency power in a surface wave mode within the heating chamber. The waveguide is coupled to the radio wave oscillator and transmits the high frequency power to the heating chamber through an opening in the wall of the heating chamber. The conductive member protrudes into the waveguide through the opening in the waveguide and is fixed to a part of the surface wave line. The rotating device rotates the object to be heated or the surface wave line.

[0004] Hereinafter, in this disclosure, high frequency power in the form of a surface wave is referred to as a surface wave, and heating by the surface wave is referred to as surface wave heating.

[0005] Patent Document 2 discloses a high-frequency heater having a disk-shaped surface wave line that radially propagates surface waves in order to improve uneven heating of an object to be heated. The high-frequency heater described in Patent Document 2 includes a surface wave line and an antenna disposed at the center of the surface wave line in order to radially propagate surface waves from the antenna. The antenna is a microwave oscillator.

[0006] Patent Document 3 discloses a surface wave generator for a high-frequency heating device that selects the intensity distribution of the generated surface waves according to the object to be heated by adjusting the height of the strip-shaped upright pieces that make up the surface wave transmission line to the object to achieve optimal heating of various objects. The surface wave generator described in Patent Document 3 includes a base made of a conductive flat plate, a plurality of strip-shaped upright pieces, an outer case, and protrusions.

[0007] The plurality of band-shaped upright bands have one end electrically connected to one surface of the base and are erected so that the surface wave generation intensity in a predetermined region of the base is different from that in other regions.

[0008] The outer case has a lower bottom on the base side, an upper bottom formed on the side corresponding to the tip of the strip-shaped upright piece and parallel to the surface of the lower bottom, and a cylindrical wall connecting the lower bottom to the upper bottom. At least the upper bottom and the cylindrical wall are made of a high-frequency low-loss resin material. The protrusion is formed on a part of the outer surface of the upper bottom of the outer case so as to protrude to a predetermined height.

[0009] JP-A-52-155442 JP-A-51-11240 JP-A-10-41064

[0010] The present disclosure provides a high-frequency heating device that fixes standing waves in a surface wave mode to multiple surface wave lines arranged two-dimensionally, and is capable of uniformly heating a wide range of objects to be heated.

[0011] A high-frequency heating device according to the present disclosure includes a plurality of surface wave lines, an oscillation source, and a power supply unit. The oscillation source supplies high-frequency power. The power supply unit transmits the high-frequency power from the oscillation source to the plurality of surface wave lines. The plurality of surface wave lines are two-dimensionally distributed and arranged independently of one another.

[0012] The high-frequency heating device according to the present disclosure can fix the position of the standing wave of the surface wave mode generated in the surface wave line and arrange multiple surface wave lines within the intended heating area, thereby enabling a wide range of objects to be heated uniformly.

[0013] FIG. 1 is a schematic diagram of a radio-frequency heating device according to a first embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating a standing wave distribution in a conventional surface wave line. FIG. 3 is a schematic diagram illustrating a standing wave distribution in a surface wave line included in the radio-frequency heating device according to the first embodiment. FIG. 4 is a schematic diagram illustrating a heating range by the surface wave line included in the radio-frequency heating device according to the first embodiment. FIG. 5 is a schematic diagram illustrating a propagation path of radio-frequency power in a conventional surface wave line. FIG. 6 is a schematic diagram illustrating a propagation path of radio-frequency power in the surface wave line included in the radio-frequency heating device according to the first embodiment. FIG. 7 is a schematic diagram illustrating a heating range by the surface wave line included in the radio-frequency heating device according to a second embodiment of the present disclosure.

[0014] (Knowledge that forms the basis of the present disclosure) At the time the inventors of the present application came up with the idea for the present disclosure, the technology of propagating high-frequency power converted into a surface wave form through a surface wave line and heating an object to be heated that is placed near the surface wave line, as described above, was already known.

[0015] According to the conventional technology described in Patent Document 1, even if the surface wave line is arranged asymmetrically with respect to the center of rotation, standing waves of a surface wave type generated in the surface wave line may cause concentric heating unevenness.

[0016] According to the conventional technology described in Patent Document 2, since the surface waves spread radially, the surface waves are strong near the antenna, which is the origin of the surface waves, but become weaker the further away from the antenna, which can result in uneven intensity of the surface waves.

[0017] Furthermore, if the object is positioned away from the antenna, the surface waves propagating along the propagation path are absorbed primarily by the portion of the object that first approaches, which can result in localized excessive heating of the object and uneven heating.

[0018] According to the conventional technology described in Patent Document 3, it is necessary to use different surface wave lines depending on the type of object to be heated. Therefore, many surface wave lines are required to configure a high-frequency heating device, which may lead to a complex configuration and an increase in size. Furthermore, even if this technology were to be put into practical use, it may be prone to errors in setting the surface wave lines, and it may take a long time to set the surface wave lines.

[0019] In this situation, the inventors of the present application came up with the idea that it would be desirable to use a small surface wave line that can fix the position of the standing wave in the surface wave mode, and to share the heating of the intended range among multiple surface wave lines, and thus came up with the subject matter of the present disclosure.

[0020] In other words, according to the high-frequency heating device of the present disclosure, by fixing the position of the standing wave of the surface wave mode generated in the surface wave line and arranging multiple surface wave lines in the intended heating range, various heated objects can be heated uniformly over a wide area.

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, for example, detailed descriptions of known matters and redundant descriptions of identical or substantially identical configurations may be omitted.

[0022] 1 to 6, a radio-frequency heating device 100 according to a first embodiment of the present disclosure will be described below. Note that the Cartesian coordinate systems shown in the following drawings have X, Y, and Z axes that indicate the left and right, front and rear, and top and bottom of the radio-frequency heating device 100, respectively. That is, the width direction, depth direction, and height direction of the radio-frequency heating device 100 are directions along the X, Y, and Z axes, respectively. The positive direction of the X, Y, and Z axes corresponds to the right, rear, and vertically upward, respectively.

[0023] Fig. 1 is a schematic diagram of a radio-frequency heating apparatus 100. As shown in Fig. 1, the radio-frequency heating apparatus 100 includes a heating chamber 1, a mounting table 3, an oscillation source 4, a waveguide 5, a feed shaft 6, a feed line 7, and two surface wave lines 8.

[0024] The heating chamber 1 is sealed with a metal wall when the front opening is closed with a door (not shown), and has a mounting table 3 arranged approximately horizontally inside. The object 2 to be heated is placed on the mounting table 3, which is a dielectric. The oscillation source 4 is a device that generates high-frequency power, such as a magnetron or a semiconductor oscillator. The waveguide 5 transmits the high-frequency power supplied from the oscillation source 4 to the power feed shaft 6.

[0025] The feed shaft 6 has a lower end 6a and an upper end 6b and is a cylindrical shaft that communicates between the waveguide 5 and the heating chamber 1. The lower end 6a is disposed inside the waveguide 5. The upper end 6b is disposed within the housing that constitutes the heating chamber 1 and below the mounting table 3. The feed line 7 is disposed within the housing that constitutes the heating chamber 1 and below the mounting table 3, and is connected to the upper end 6b of the feed shaft 6.

[0026] High-frequency power is transmitted from the oscillation source 4 through the waveguide 5 and the feed shaft 6 to the feed line 7 and the heating chamber 1. The feed line 7 is disposed between two surface wave lines 8. One end of the feed line 7 is connected to one of the two surface wave lines 8, and the other end of the feed line 7 is connected to the other of the two surface wave lines 8. With this configuration, the feed line 7 transmits high-frequency power evenly from the feed shaft 6 to each of the two surface wave lines 8.

[0027] In this embodiment, the waveguide 5 , the feed shaft 6 and the feed line 7 constitute a feed section 20 that transmits high-frequency power from the oscillation source 4 to the two surface wave lines 8 .

[0028] The surface wave line 8 converts the received high frequency power into a surface wave form. This high frequency power in the surface wave form heats the object 2 to be heated, which is placed near the surface wave line 8, and browns the object 2 to be heated.

[0029] The surface wave line 8 is connected to the feed shaft 6 via a feed line 7. The feed shaft 6 is connected to a motor (not shown) and rotates in conjunction with the rotation of the motor. That is, the feed shaft 6 functions as a rotation shaft that rotatably supports the feed line 7 and the surface wave line 8.

[0030] Fig. 2 is a schematic diagram illustrating the standing wave distribution in a conventional surface wave line 80. As shown in Fig. 2, the surface wave line 80 has a periodic structure including a plurality of stubs 81 that are erected parallel to one another at regular intervals on a base.

[0031] The surface wave line 80 converts the supplied high frequency power into high frequency power in a surface wave mode. The surface wave line 80 transmits the high frequency power in a surface wave mode, i.e., surface waves, in a propagation direction 12 near the tips of the multiple stubs 81. The propagation direction 12 is a direction perpendicular to the multiple stubs 81, i.e., a radial direction perpendicular to the feed axis 6 and centered on the feed axis 6.

[0032] Hereinafter, the vicinity of the tips of the multiple stubs 81 will be collectively referred to as the tip portion 16 of the surface wave line 80. The length of the surface wave line 80 along the propagation direction 12 will be referred to as the length of the surface wave line 80. This also applies to the surface wave line 8 (described later) according to this embodiment.

[0033] The surface wave line 80 has a natural resonance mode. When high-frequency power is supplied to the surface wave line 80, a distribution of resonance currents occurs essentially at intervals of 1 / 2 wavelength. In connection with the distribution of resonance currents, a distribution of standing waves 9 of surface waves occurs near the tip 16. Note that 1 / 2 wavelength means 1 / 2 the length of the wavelength of the resonance current. In other words, one wavelength, which will be described later, is the length of the wavelength of the resonance current.

[0034] Changing the excitation frequency depending on the type of heated object 2 changes the wavelength. The number of standing waves 9 also changes accordingly. For example, when increasing the four standing waves 9a shown in FIG. 2 to five standing waves 9b, the excitation frequency must be increased by 5 / 4 to make the wavelength 4 / 5 times the original wavelength. The more standing waves 9 generated in the surface wave line 8, the smaller the change in the wavelength (frequency) of the standing waves 9, and the easier it is for the resonant mode of the surface wave line 8 to switch.

[0035] Fig. 3 is a schematic diagram for explaining the standing wave distribution in the surface wave line 8 provided in the high-frequency heating apparatus 100 according to this embodiment. As shown in Fig. 3, each of the two surface wave lines 8 shown in Fig. 1 has a periodic structure including a plurality of stubs 81 standing parallel to each other at regular intervals on a base, similar to the surface wave line 80. The surface wave line 8 differs from the conventional surface wave line 80 shown in Fig. 2 in that the surface wave line 8 has a length less than one wavelength.

[0036] As a result, one standing wave 9 is distributed near the surface wave line 8 (see FIG. 3). In order to increase the number of standing waves 9 from one to two, that is, to halve the wavelength of the standing waves 9, the excitation frequency must be doubled.

[0037] However, if the excitation frequency required for this exceeds the operating frequency range of the oscillation source 4, the resonance mode in the surface wave line 8 will not be switched. According to this embodiment, by using a surface wave line 8 having a length of less than one wavelength, the number of standing waves 9 in the form of surface waves generated near the surface wave line 8 can be fixed to one.

[0038] Fig. 4 is a schematic diagram for explaining the heating range by the surface wave line 8 provided in the high-frequency heating device 100 according to this embodiment. Fig. 4 schematically shows the surface wave line 8 shown in Fig. 1 as viewed from above. For the sake of explanation, Fig. 4 only shows the feed shaft 6, the feed line 7, and the surface wave line 8. Hereinafter, the view from above will be referred to as a plan view.

[0039] As shown in Fig. 4, the surface wave line 8 includes a surface wave line 8a, a surface wave line 8b, a surface wave line 8c, and a surface wave line 8d. Each of the surface wave lines 8a to 8d has a length of less than one wavelength. The surface wave lines 8a to 8d are two-dimensionally dispersed and arranged independently of one another on a plane substantially parallel to the mounting table 3. The surface wave lines 8a and 8b are connected to the feeder shaft 6 via a feeder line 7 and are rotatable integrally with the feeder shaft 6, which is the rotation axis.

[0040] Specifically, the feeder lines 7 include two first feeder lines (7a, 7c) and two second feeder lines (7b, 7d).

[0041] The first feed line 7a connects the surface wave lines 8a and 8b. The second feed line 7b connects the feed shaft 6 to the first feed line 7a. Thus, high frequency power from the feed shaft 6 is transmitted to the surface wave lines 8a and 8b via the first feed line 7a and the second feed line 7b.

[0042] The first feed line 7c connects the surface wave lines 8c and 8d. The second feed line 7d connects the feed shaft 6 to the first feed line 7c. Thus, high frequency power from the feed shaft 6 is transmitted to the surface wave lines 8c and 8d via the first feed line 7c and the second feed line 7d.

[0043] The first feed line 7a is perpendicular to the second feed line 7b, and the first feed line 7c is perpendicular to the second feed line 7d. The second feed line 7b and the second feed line 7d extend in opposite directions from the feed axis 6 and are aligned in a straight line. The first feed line 7a is parallel to the first feed line 7c. With this configuration, the multiple surface wave lines 8 (8a to 8d) and the feed lines 7 (7a to 7d) have a substantially H-shape in plan view.

[0044] The surface wave lines 8a and 8b are arranged at the same distance from the feed axis 6. The surface wave lines 8c and 8d are also arranged at the same distance from the feed axis 6. The distance between the surface wave line 8c or 8d and the feed axis 6 is longer than the distance between the surface wave line 8a or 8b and the feed axis 6.

[0045] Specifically, in a plan view, the distance from the feed axis 6 to the closest portion of the surface wave lines 8a and 8b (a first pair 8Px, described later) is very small, approaching zero. The distance from the feed axis 6 to the farthest portion of the surface wave lines 8a and 8b (a first pair 8Px) is approximately the same as the distance from the feed axis 6 to the location of the closest surface wave lines 8c and 8d (a second pair 8Py, described later).

[0046] When the power feed shaft 6 rotates, the surface wave lines 8a and 8b (first pair 8Px) rotate within the range of the rotation area 10x and perform surface wave heating on the object 2 placed above the rotation area 10x. In addition, the surface wave lines 8c and 8d (second pair 8Py) rotate within the range of the rotation area 10y and perform surface wave heating on the object 2 placed above the rotation area 10y. This allows the surface wave lines 8a to 8d to share the heating range on the mounting table 3 without any gaps.

[0047] In other words, the rotational region 10x has a disk shape centered on the power supply axis 6. The rotational region 10y has an annular shape centered on the power supply axis 6 and is disposed outside the rotational region 10x so as to surround the rotational region 10x. Both the rotational regions 10x and 10y are parallel to the XY plane (i.e., horizontal).

[0048] The distance from the feed shaft 6 to the surface wave lines 8a and 8b (first pair 8Px) and the distance from the feed shaft 6 to the surface wave lines 8c and 8d (second pair 8Py) are set so that no gap is left between the rotation regions 10x and 10y.

[0049] As described above, the surface wave lines 8a to 8d have lengths less than one wavelength. Therefore, each of the surface wave lines 8a to 8d can excite only one standing wave 9 in a surface wave mode. In other words, the high-frequency power in a surface wave mode excited by the surface wave lines 8a to 8d is stable without fluctuation. This enables stable heating of the object 2 placed near the rotating region 10x and the rotating region 10y.

[0050] 4, a plane 11 is a plane that includes the feed axis 6 and is aligned with the feed axis 6. That is, the plane 11 is a plane that is perpendicular to the mounting table 3. The surface wave lines 8a and 8b constitute a first pair of surface wave lines 8 that are arranged symmetrically with respect to the plane 11. Similarly, the surface wave lines 8c and 8d constitute a second pair of surface wave lines 8 that are arranged symmetrically with respect to the plane 11.

[0051] In the first pair of surface wave lines 8, the surface wave lines 8a and 8b have the same heating performance, and in the second pair of surface wave lines 8, the surface wave lines 8c and 8d have the same heating performance. Hereinafter, the first pair of surface wave lines 8 will be referred to as a first pair 8Px, and the second pair of surface wave lines 8 will be referred to as a second pair 8Py. The first pair 8Px and the second pair 8Py will be collectively referred to as a pair 8P.

[0052] The propagation direction 12a of the surface waves in the surface wave line 8a is aligned with the propagation direction 12b of the surface waves in the surface wave line 8b, but their directions are opposite to each other. The propagation direction 12c of the surface waves in the surface wave line 8c is aligned with the propagation direction 12d of the surface waves in the surface wave line 8d, but their directions are opposite to each other.

[0053] In the second feed line 7b, the feed direction 13x of the high frequency power from the feed shaft 6 is substantially perpendicular to the propagation directions 12a and 12b of the surface waves. In the second feed line 7d, the feed direction 13y of the high frequency power from the feed shaft 6 is substantially perpendicular to the propagation directions 12c and 12d of the surface waves and is opposite to the feed direction 13x.

[0054] "Substantially orthogonal" not only literally means "orthogonal," but also takes into consideration errors due to variations in the arrangement of the surface wave lines 8a to 8d and their connection to the feeder line 7. In this embodiment, "substantially orthogonal" means that the angle between two straight lines or two planes is in the range of 90°±5°.

[0055] With the above configuration, the surface wave lines 8a and 8b included in the first pair 8Px are supplied with equally divided power, and similarly, the surface wave lines 8c and 8d included in the second pair 8Py are supplied with equally divided power.

[0056] Therefore, in the rotation area 10x, the surface wave lines 8a and 8b uniformly heat the object 2, thereby suppressing uneven heating. In the rotation area 10y, the surface wave lines 8c and 8d uniformly heat the object 2, thereby suppressing uneven heating.

[0057] Since the rotating region 10x is located inside the rotating region 10y, the surface wave lines 8a and 8b included in the first pair 8Px move slower than the surface wave lines 8c and 8d included in the second pair 8Py, i.e., the surface wave lines 8a and 8b have a stronger heating intensity than the surface wave lines 8c and 8d.

[0058] Taking this characteristic into consideration, the heating performance of the surface wave lines 8a and 8b and the heating performance of the surface wave lines 8c and 8d are adjusted to achieve a balance between heating of the object 2 in the rotation area 10x and the rotation area 10y.

[0059] According to the above configuration, the heating range by surface wave heating can be widened and uneven heating can be suppressed.

[0060] Next, characteristics of this embodiment that differ from those of the conventional technology will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a schematic diagram for explaining the propagation path of high-frequency power in a conventional surface wave line 80. Fig. 6 is a schematic diagram for explaining the propagation path of high-frequency power in a surface wave line 8 provided in the high-frequency heating device 100 according to this embodiment.

[0061] 5 and 6 , high-frequency power is supplied to the surface wave lines 8 and 80 from a propagation starting point 14. The propagation starting point 14 in Fig. 5 is one of two ends of a propagation path 15 along the propagation direction 12 that is connected to the feed shaft 6. The propagation starting point 14 in Fig. 6 is one of two ends of the propagation path 15 along the propagation direction 12 that is connected to the feed line 7.

[0062] The propagation path 15 is a path from the propagation starting point 14 to the end of the surface wave line 8 in the propagation direction 12 at the tip 16. That is, the propagation path 15 is formed at the tip 16. When a surface wave propagates along the propagation path 15 from the propagation starting point 14 in the propagation direction 12, the object 2 to be heated, which is arranged near the surface wave line 8, is heated.

[0063] 5 , when the object 2 to be heated is positioned away from the propagation origin 14, the propagation origin 14 does not come into contact with the bottom surface of the object 2. In this case, in the part of the object 2 to be heated that the surface wave propagating in the propagation direction 12 on the propagation path 15 first approaches, the heated region 17 in the object 2 not only spreads in the propagation direction 12 along the bottom surface of the object 2, but also spreads upward as the side surfaces of the object 2 are exposed to the surface waves.

[0064] As a result, more surface waves are absorbed at the end (the left end in FIG. 5) of the object 2 than at other parts, which may result in localized excessive heating of the object 2.

[0065] This localized heating of the object 2 occurs when the object 2 is placed at a position displaced from the predetermined position or when multiple objects 2 are placed, causing the object 2 to be displaced from the feed shaft 6 on the surface wave line 80. That is, as shown in Fig. 5 , when the object 2 is placed at a distance from the feed shaft 6, the surface wave line 80 overlaps with the feed shaft 6 in a plan view, but the object 2 does not overlap with the feed shaft 6.

[0066] Therefore, as will be explained below, it is desirable to have a configuration in which the surface wave line 8 is not disposed above the feed axis 6.

[0067] 6, the feeder line 7 is disposed at a position away from the tip 16 of the surface wave line 8. That is, in plan view, neither the surface wave line 8 nor the object 2 to be heated overlaps with the feeder axis 6 of the feeder line 7.

[0068] Therefore, the object 2 to be heated is positioned slightly off the power supply axis 6, while the propagation starting point 14 faces the bottom surface of the object 2. Therefore, the heated area 17 does not spread upward, but spreads only in the propagation direction 12 on the propagation path 15. As a result, localized heating of the object 2 to be heated can be suppressed.

[0069] As described above, in this embodiment, the surface wave line 8 is not disposed above the power feed shaft 6, and the power feed line 7 is disposed at a position away from the tip 16 that faces the object to be heated 2. This makes it possible to suppress localized heating of the object to be heated 2 even if the object to be heated 2 is disposed away from the power feed shaft 6 of the surface wave line 8.

[0070] 4, in a plan view, the feeder line 7 is configured in a substantially H-shape with respect to the surface wave lines 8a and 8b included in the first pair 8Px and the surface wave lines 8c and 8d included in the second pair 8Py. Furthermore, the first pair 8Px and the second pair 8Py are arranged so that their distances from the feed axis 6 are different from each other.

[0071] That is, in a plan view, the feeder lines connecting the pairs of surface wave lines 8 are arranged asymmetrically with respect to the feeder axis 6. This configuration makes it possible to widen the heating range by surface wave heating and to suppress uneven heating due to localized heating.

[0072] [Effects, etc.] The high-frequency heating device 100 according to this embodiment includes a plurality of surface wave lines 8, an oscillation source 4, and a power supply unit 20 (waveguide 5, feed shaft 6, feed line 7). The oscillation source 4 supplies high-frequency power. The power supply unit 20 transmits the high-frequency power from the oscillation source 4 to the plurality of surface wave lines 8. The plurality of surface wave lines 8 are distributed two-dimensionally and arranged independently of one another.

[0073] This makes it possible to fix the position of the standing wave 9 in the form of a surface wave generated on the surface wave line 8. Therefore, by arranging a plurality of surface wave lines 8 in the intended heating range, it is possible to heat various objects 2 to a desired state uniformly over a wide range.

[0074] In the high-frequency heating device 100 according to this embodiment, the power supply unit 20 may include a power supply shaft 6 that functions as a rotation shaft that rotatably supports the plurality of surface wave lines 8. The plurality of surface wave lines 8 may be arranged such that when the plurality of surface wave lines 8 are rotated about the power supply shaft 6, the plurality of surface wave lines 8 pass through a plurality of different regions when viewed along the power supply shaft 6.

[0075] This allows the heating range to be widened by surface wave heating, and as a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0076] In the high-frequency heating device 100 according to this embodiment, the power supply unit 20 may further include a power supply line 7 arranged above the power supply shaft 6 and connecting the power supply shaft 6 to each of the plurality of surface wave lines 8.

[0077] As a result, even if the object 2 is positioned away from the power supply shaft 6, the surface waves propagate only along the bottom surface of the object 2, not along the sides of the object 2. This makes it possible to suppress localized heating of the object 2. As a result, various objects 2 can be heated uniformly over a wide range to a desired state.

[0078] In the high-frequency heating device 100 according to this embodiment, each of the surface wave lines 8 may have a length less than one wavelength.

[0079] As a result, only one standing wave 9 in a surface wave mode can be excited in each of the multiple surface wave lines 8. This suppresses the switching of the resonance mode in the surface wave line 8, and the surface wave line 8 can excite high frequency power in a surface wave mode in a stable state. As a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0080] In the high-frequency heating device 100 according to this embodiment, each of the plurality of surface wave lines 8 may have a tip portion 16 arranged to face the object to be heated 2. Each of the plurality of surface wave lines may be connected to the power supply unit 20 at a position away from the tip portion 16.

[0081] As a result, even if the object 2 is positioned away from the power supply shaft 6, the surface waves propagate only along the bottom surface of the object 2, not along the sides of the object 2. This makes it possible to suppress localized heating of the object 2. As a result, various objects 2 can be heated uniformly over a wide range to a desired state.

[0082] In the high-frequency heating apparatus 100 according to this embodiment, the plurality of surface wave lines may include a pair of surface wave lines 8 arranged symmetrically with respect to a plane including the feed axis. The pair of surface wave lines 8 constitutes a pair 8P. The pair of surface wave lines 8 included in the pair 8P may have the same performance.

[0083] This allows the performance of the pair of surface wave lines 8 included in the pair 8P to be equalized, thereby enabling surface wave heating. As a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0084] In the high-frequency heating device 100 according to this embodiment, the feeder line 7 includes a first feeder line (7a, 7c) connecting the pair 8P, and the pair of surface wave lines 8 included in the pair 8P may be aligned in a straight line. That is, the pair 8P may be arranged so that the propagation directions 12a, 12b of the two surface waves in the pair of surface wave lines 8 are aligned in a straight line.

[0085] This allows the performance of the pair of surface wave lines 8 included in the pair 8P to be equalized, thereby enabling surface wave heating. As a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0086] In the high-frequency heating apparatus 100 according to this embodiment, the feeder line 7 may further include second feeder lines (7b, 7d) that connect the feed shaft 6 to the first feeder line (7a, 7c) and are capable of transmitting high-frequency power to the pair 8P. The first feeder lines 7a, 7c may be substantially perpendicular to the second feeder lines 7b, 7d, respectively.

[0087] This allows the performance of the pair of surface wave lines 8 included in the pair 8P to be equalized, thereby enabling surface wave heating. As a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0088] In the high-frequency heating apparatus 100 according to this embodiment, the multiple surface wave lines 8 may include a first pair of surface wave lines 8 and a second pair of surface wave lines 8. The first pair of surface wave lines 8 is a first pair 8Px, and the second pair of surface wave lines 8 is a second pair 8Py. Note that the first pair of surface wave lines 8 (first pair 8Px) and the second pair of surface wave lines 8 (second pair 8Py) are each equivalent to the above-described pair of surface wave lines 8 (pair 8P).

[0089] This allows the heating range to be widened by surface wave heating, and as a result, various objects 2 to be heated can be heated uniformly over a wide range to a desired state.

[0090] In the high frequency heating device 100 according to this embodiment, the first pair of surface wave lines 8 may have different performance from the second pair of surface wave lines 8 .

[0091] This allows the heating performance to be adjusted between the first pair 8Px and the second pair 8Py while widening the heating range by surface wave heating, thereby enabling various objects 2 to be heated uniformly over a wide range to a desired state.

[0092] In the high-frequency heating apparatus 100 according to this embodiment, the first pair of surface wave lines 8 may be aligned in a straight line. The second pair of surface wave lines 8 may be aligned in a straight line. The first pair of surface wave lines 8 may be substantially parallel to the second pair of surface wave lines 8.

[0093] The second feeder line 7b for the first pair of surface wave lines 8 and the second feeder line 7d for the second pair of surface wave lines 8 may extend in opposite directions and be aligned in a straight line.

[0094] The first feeder line 7a and the second feeder line 7b for the first pair of surface wave lines 8 may be different in at least one of size and shape in a plan view from the first feeder line 7c and the second feeder line 7d for the second pair of surface wave lines 8. That is, in a plan view, the feeder line connecting the plurality of pairs of surface wave lines 8 may be configured in a substantially H-shape, and the plurality of pairs of surface wave lines 8 may be arranged asymmetrically with respect to the feed axis 6.

[0095] As a result, even if the object 2 is positioned away from the power supply shaft 6, which is the rotation axis of the surface wave line 8, the surface waves propagate only along the bottom surface of the object 2, not along the sides of the object 2. This makes it possible to suppress localized heating of the object 2. As a result, various objects 2 can be heated uniformly over a wide range to a desired state.

[0096] Second Embodiment Hereinafter, a high-frequency heating device 100 according to a second embodiment of the present disclosure will be described with reference to Fig. 7. Fig. 7 is a schematic diagram for explaining the heating range by the surface wave line 8 included in the high-frequency heating device 100 according to the second embodiment.

[0097] 7, the surface wave line 8 includes a surface wave line 8e and a surface wave line 8f. Each of the surface wave lines 8e and 8f has a length of less than one wavelength. The surface wave lines 8e and 8f are two-dimensionally dispersed and arranged independently of each other on a plane substantially parallel to the mounting table 3. The surface wave lines 8e and 8f are connected to the feed shaft 6 via a feed line 7 and are rotatable integrally with the feed shaft 6, which is the rotation axis.

[0098] Specifically, the feeder lines 7 include two first feeder lines (7h, 7j) and two second feeder lines (7i, 7k).

[0099] The surface wave line 8e is connected to the first feed line 7h. The second feed line 7i connects the feed shaft 6 to the first feed line 7h. Thus, high-frequency power from the feed shaft 6 is transmitted to the surface wave line 8e via the first feed line 7h and the second feed line 7i.

[0100] The surface wave line 8f is connected to the first feed line 7j. The second feed line 7k connects the feed shaft 6 to the first feed line 7j. Thus, high-frequency power from the feed shaft 6 is transmitted to the surface wave line 8f via the first feed line 7j and the second feed line 7k.

[0101] The first feeder line 7h is perpendicular to the second feeder line 7i, and the first feeder line 7j is perpendicular to the second feeder line 7k. The second feeder line 7i and the second feeder line 7k are aligned in a straight line. The first feeder line 7h is parallel to the first feeder line 7j. With this configuration, the multiple surface wave lines 8 (8e, 8f) and the feeder lines 7 (7h to 7k) have a generally crank-shaped configuration in plan view.

[0102] The distance between the surface wave line 8f and the feed axis 6 is longer than the distance between the surface wave line 8e and the feed axis 6. More specifically, in a plan view, the distance from the feed axis 6 to the closest portion of the surface wave line 8e is very small, close to zero. The distance from the feed axis 6 to the farthest portion of the surface wave line 8e is approximately the same as the distance from the feed axis 6 to the closest location of the surface wave line 8f.

[0103] When the power supply shaft 6 rotates, the surface wave line 8e rotates within the range of the rotation region 10p and performs surface wave heating on the object 2 placed above the rotation region 10p. In addition, the surface wave line 8f rotates within the range of the rotation region 10q and performs surface wave heating on the object 2 placed above the rotation region 10q. This allows the surface wave lines 8e and 8f to share the heating range on the mounting table 3 without any gaps.

[0104] In other words, the rotational region 10p has a disk shape centered on the feed shaft 6. The rotational region 10q has a circular ring shape centered on the feed shaft 6 and is disposed outside the rotational region 10p so as to surround the rotational region 10p. Both the rotational regions 10p and 10q are parallel to the XY plane (i.e., horizontal). The distances from the feed shaft 6 to the surface wave line 8e and the surface wave line 8f are set so that no gap is formed between the rotational regions 10p and 10q.

[0105] As described above, the surface wave lines 8e and 8f have lengths less than one wavelength. Therefore, each of the surface wave lines 8e and 8f can excite only one standing wave 9 (see FIG. 3) of a single surface wave form. That is, the surface waves excited by the surface wave lines 8e and 8f are stable and do not fluctuate. As a result, stable heating of the object 2 placed near the rotating region 10p and the rotating region 10q is possible.

[0106] Because the rotation region 10p is located more inward than the rotation region 10q, the surface wave line 8e moves slower than the surface wave line 8f. That is, the surface wave line 8e has a stronger heating intensity than the surface wave line 8f. Taking this characteristic into consideration, the heating performance of the surface wave line 8e and the heating performance of the surface wave line 8f are adjusted to achieve a balance between the heating of the object 2 in the rotation region 10p and the rotation region 10q.

[0107] The propagation direction 12e of the surface wave in the surface wave line 8e is parallel to the propagation direction 12f of the surface wave in the surface wave line 8f, and the directions are opposite to each other.

[0108] According to the above configuration, the heating range by surface wave heating can be widened and uneven heating can be suppressed.

[0109] Other configurations and effects of this embodiment are the same as or substantially the same as those of the first embodiment, and therefore description thereof will be omitted.

[0110] The present disclosure is applicable to a high-frequency heating device capable of performing surface wave heating.

[0111] REFERENCE SIGNS LIST 1 heating chamber 2 object to be heated 3 mounting table 4 oscillation source 5 waveguide 6 feed axis 6a lower end 6b upper end 7 feed line 7a, 7c, 7h, 7j first feed line 7b, 7d, 7i, 7k second feed line 8, 8a, 8b, 8c, 8d, 8e, 8f, 80 surface wave line 8P pair 8Px first pair 8Py second pair 9, 9a, 9b standing wave 10x, 10y, 10p, 10q rotation region 11 surface 12, 12a, 12b, 12c, 12d, 12e, 12f propagation direction 13x, 13y power supply direction 14 propagation origin 15 propagation path 16 tip 17 heating region 20 power supply section 81 Stub 100 High frequency heating device

Claims

1. A high-frequency heating device comprising: a plurality of surface wave lines; an oscillation source configured to supply high-frequency power; and a power supply unit that transmits the high-frequency power from the oscillation source to the plurality of surface wave lines, wherein the plurality of surface wave lines are distributed two-dimensionally and arranged independently of one another.

2. The high frequency heating device according to claim 1, wherein the power supply section includes a power supply shaft that functions as a rotation shaft that rotatably supports the plurality of surface wave lines, and the plurality of surface wave lines are arranged so that when the plurality of surface wave lines are rotated, the plurality of surface wave lines pass through a plurality of mutually different regions.

3. The high frequency heating device according to claim 2, wherein the power supply unit further comprises a power supply line arranged above the power supply shaft and connecting the power supply shaft to each of the plurality of surface wave lines.

4. The high frequency heating device according to claim 1 or 2, wherein each of the plurality of surface wave lines has a length less than one wavelength.

5. A high frequency heating device according to claim 1 or 2, wherein each of the plurality of surface wave lines has a tip portion arranged to face the object to be heated, and each of the plurality of surface wave lines is connected to the power supply portion at a position away from the tip portion.

6. The high frequency heating device according to claim 3, wherein the plurality of surface wave lines include a pair of surface wave lines arranged symmetrically with respect to a plane including the feed axis, and the pair of surface wave lines have the same performance.

7. The high frequency heating device according to claim 6, wherein the feeder line includes a first feeder line connecting the pair of surface wave lines, and the pair of surface wave lines are aligned in a straight line.

8. The high frequency heating device according to claim 7, wherein the feed line further includes a second feed line that connects the feed axis to the first feed line and is capable of transmitting the high frequency power to the pair of surface wave lines, and the first feed line is substantially perpendicular to the second feed line.

9. The high frequency heating device according to claim 8, wherein the plurality of surface wave lines include a first pair of surface wave lines and a second pair of surface wave lines, and each of the first pair of surface wave lines and the second pair of surface wave lines is a pair of surface wave lines.

10. The high frequency heating device according to claim 9, wherein the first pair of surface wave lines has different performance from the second pair of surface wave lines.

11. The high frequency heating device according to claim 9 or 10, wherein the first pair of surface wave lines are aligned in a straight line, the second pair of surface wave lines are aligned in a straight line, the first pair of surface wave lines are substantially parallel to the second pair of surface wave lines, the second feed line for the first pair of surface wave lines and the second feed line for the second pair of surface wave lines extend in opposite directions and are aligned in a straight line, and the first feed line and the second feed line for the first pair of surface wave lines differ from the first feed line and the second feed line for the second pair of surface wave lines in at least one of size and shape.

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