JP7372684B2 - Heating devices and heating plates - Google Patents

Description

The present invention relates to a heating device used for heat treatment of various plate-like members or sheet-like members such as glass substrates, semiconductor lead frames, other metal plates, and synthetic resin plates.

Equipment for heat treating relatively large glass substrates, which are components of liquid crystal display panels, etc., uses a large number of shelf-shaped heaters consisting of double-sided far-infrared panel heaters that emit far-infrared rays from both sides by heating a heat sink. , a heating furnace has been proposed in which heaters are arranged in multiple stages at regular intervals in the vertical direction within a furnace main body, and each space formed between these shelf heaters is used as a drying chamber (see Patent Document 1).

In the case of the heating furnace described in Patent Document 1, since a large number of shelf-shaped heaters consisting of double-sided far-infrared panel heaters are arranged, each space (drying area) formed between these shelf-shaped heaters is It is superior in that it can efficiently heat the room (room).

However, the heat emitted from the many shelf-shaped heaters arranged vertically tends to rise inside the heating furnace and collect in the area near the top wall of the furnace, so the temperature in the upper area of the furnace is The temperature becomes higher than that of the lower region of the furnace, and it is extremely difficult to eliminate such a temperature difference between the upper region of the furnace and the lower region of the furnace.

Patent Document 2 discloses a plurality of heating walls disposed facing each other at a distance in a space surrounded by a heat insulating material, a heat generating means provided on the heating walls, and a distance between the heating walls. a plurality of heat transfer walls disposed apart from each other, a plurality of heat radiating members disposed in a shelf-like manner between the heat transfer walls, and a cover provided between vertically adjacent heat radiating members. The present disclosure discloses a heating device having a configuration including a heating space for heating an object.
Since the heating device disclosed in Patent Document 2 performs heating using a heating wall provided in the vertical direction, the size of the object to be heated that can be accommodated in the heating space is limited. The technology disclosed in Patent Document 2 does not assume that a large-area plate-shaped or sheet-shaped object to be heated is heated uniformly in the first place, so it is difficult to uniformly heat the temperature within the surface of a large-area object to be heated. It is difficult to do so.

Japanese Patent Application Publication No. 2001-317872 Japanese Patent Application Publication No. 2005-352306

In general, it is difficult to make the temperature distribution uniform over a wide area with high accuracy because the heating device is placed in the atmosphere and is constantly affected by external disturbances. If a large number of heaters and a large number of temperature sensors are installed to control the temperature within the surface, it is possible to uniformly heat a wide area with high precision, but the cost of the device increases. Furthermore, when a large number of heaters and a large number of temperature sensors are installed, it is difficult to stack the heating spaces vertically.

The problem to be solved by the present invention is to provide a heating device that can uniformly heat a large-area plate-shaped or sheet-shaped object at low cost.

The heating device of the present invention includes a plurality of heating plates arranged at intervals in the vertical direction;
a heating space for accommodating an object to be heated, defined by heating surfaces of the heating plates facing each other in the vertical direction;
Each of the heating plates is
A rectangular metal plate,
a plurality of heating element elements built into the metal plate and wired with heating wires;
The plurality of heating element elements are arranged in a first direction of the metal plate and each extend in a second direction perpendicular to the first direction,
The plurality of heating element elements have varying widths or varying arrangement intervals in the first direction,
In the second direction, the wiring density of the heating wires of each of the plurality of heating elements changes.

According to the present invention, a heating space is defined between opposing heating plates, and the configuration of the heating element built into the heating plate is optimized, so that a large-area plate or sheet-shaped object to be heated can be uniformly heated. Can be heated.

FIG. 1 is a front view showing a heating device that is an embodiment of the present invention. FIG. 2 is an enlarged view showing a portion surrounded by a circle indicated by arrow A in FIG. 1; FIG. 2 is a side view of the heating device shown in FIG. 1; FIG. 4 is an enlarged side view of a portion surrounded by an ellipse indicated by arrow B in FIG. 3, showing how an object to be heated is placed and set in the heating space of the heating device shown in FIG. 1; FIG. 4B is a side view corresponding to FIG. 4A, illustrating how the object to be heated is set in the heating space of the heating device shown in FIG. 1; FIG. 4B is a side view corresponding to FIG. 4A, showing how the object to be heated is taken out from the heating space of the heating device shown in FIG. 1; 2 is a plan view showing an embodiment of a heating plate employed in the heating device shown in FIG. 1. FIG. FIG. 6 is a front view of the heating plate shown in FIG. 5. FIG. 6 is a plan view conceptually showing the state of the wiring of the heating wire elements installed inside the heating plate shown in FIG. 5; FIG. 2 is a front view showing another embodiment of a heating plate employed in the heating device shown in FIG. 1; FIG. 9 is a plan view of the heating plate shown in FIG. 8; 9 is a schematic diagram of a rod-shaped heater installed inside the heating plate shown in FIG. 8. FIG. FIG. 3 is an exploded perspective view showing an object to be heated, a guide member that guides the object to be heated to a heating space, and a heating plate. FIG. 3 is a perspective view showing how pins are erected on the heating element so that the object to be heated does not come into direct contact with the heating surface of the heating plate in the heating space. FIG. 2 is an exploded perspective view conceptually showing that when the object to be heated is a sheet-like object, the object to be heated is fixed to a frame and guided to a heating space along a guide member. When a sheet-like object to be heated is fixed to the frame, pins are placed upright on the heating plate in accordance with the jig position so that the frame does not come into direct contact with the heating plate in the heating space. FIG. FIG. 2 is a front view showing that the heating device shown in FIG. 1 includes a back plate provided at the back of the heating space, which has a plurality of gas supply holes for supplying gas into the heating space. FIG. 3 is a side view showing how inert gas is supplied into the heating space. A sectional view taken along the line CC in FIG. 5. FIG. 18 is an enlarged view showing a portion surrounded by a circle indicated by arrow D in FIG. 17;

Hereinafter, a heating device 1 that is an embodiment of the present invention will be described based on the drawings.
As shown in FIGS. 1 to 7, the heating device 1 has a plurality of rectangular heating plates 10 arranged at equal intervals in the vertical direction, and has a plate shape defined by the opposing heating plates 10, 10. Alternatively, it has a heating space 30 for accommodating the sheet-shaped object to be heated 20. In addition, it has a temperature adjustment device 40 for adjusting the temperature of each heating plate 10. Note that although the heating plates 10 are arranged at equal intervals in the vertical direction, the arrangement is not limited thereto, and they may not be arranged at equal intervals.

FIG. 1 shows the front side of the heating device 1. The left and right ends of the plurality of heating plates 10 on the front side are supported by a pair of left and right support plates 50L and 50R, and the left and right ends on the back side are also supported. Similarly, it is supported by a pair of left and right support plates 50L and 50R. Each of the pair of support plates 50L and 50R on the front side and the back side is arranged to face each other, and a plurality of grooves 51 having a rectangular cross section are formed on the opposing surfaces at equal intervals in the vertical direction (the height of the heating space 30). (equivalent to the length of the ridge) and is formed horizontally (see Figures 1 and 2). The left and right end portions of the front side and back side of the heating plate 10 are respectively fitted into the plurality of grooves 51, and the respective heating plates 10 are positioned in the vertical direction. The object to be heated accommodated in the heating space 30 is heated by the upper and lower heating plates 10.

The front side and back side of the heating space 30 are open, and both sides of the heating space 30 are open between the support plates 50L, 50L and between the support plates 50R, 50R. That is, the heating space 30 is open on all four sides.
By providing each heating space 30 with an opening, it becomes possible to continuously connect the heat treatment process by the heating device 1 with other processes.

On the opposing surfaces of each pair of support plates 50L and 50R, belt-shaped guide members 60L and 60R with an L-shaped cross section for guiding the object to be heated 20 into the heating space 30 are located slightly above the grooves 51 (not shown). It is fixed using screws or the like (see FIGS. 1 to 3 and FIG. 11). The guide members 60L and 60R are arranged horizontally in the front-back direction L of the heating device 1 (see FIG. 3). Guide members 61L and 61R for smoothly guiding the object to be heated 20 into the heating space 30 are attached to the front sides of the guide members 60L and 60R (the front side of the heating device 1, the left side in FIG. 3).

The upper and lower end sides of the pair of support plates 50L and 50R on the front side and back side of the heating device 1 are connected by a top plate 71 and a bottom plate 72, respectively. Shorter leg members 73L and 73R are attached to the lower surface of the bottom plate 72, respectively, and the lower ends of these leg members 73L and 73R are fixed to the middle plate 74. Longer leg members 75L and 75R are attached to the lower surface of the middle plate 74, respectively, and the lower ends of these leg members 75L and 75R are fixed to the base 76.

A pair of left and right support plates 50L, 50R on the front side of the heating device 1 and a pair of left and right support plates 50L, 50R on the back side are formed of stainless steel, and include a top plate 71, a bottom plate 72, leg members 73L, 73R, and a middle plate. 74, the leg members 75L, 75R and the base 76 are preferably made of stainless steel, which is the same material as the pair of left and right support plates 50L, 50R, but are not limited to this, and are made of aluminum or aluminum alloy (or radiant heat It may also be made of aluminum or an aluminum alloy (aluminum or aluminum alloy) that has been subjected to a matte surface treatment to suppress divergence.

As shown in FIG. 4A, the plate-shaped object to be heated 20 is horizontally inserted into the heating space 30 from the guiding members 61L and 61R. As shown in FIG. 4B, the object to be heated 20 is heated while being sandwiched between the upper and lower heating plates 10. After the heat treatment, the object to be heated 20 is carried out in the horizontal direction from the opening on the back side opposite to the guiding members 61L and 61R, as shown in FIG. 4C.

Here, the heating plate 10 of this embodiment will be explained.
The heating plate 10 includes three heating elements 11A, 11B, and 11C, as shown in FIGS. 5 to 7. Here, the direction in which the heating element elements 11A, 11B, and 11C are arranged is referred to as an arrangement direction L (first direction), and the direction in which the heating element elements 11A, 11B, and 11C extend is referred to as an extending direction W (second direction). direction).
Each of the heating element elements 11A, 11B, and 11C is a so-called surface structure in which heating wires 13A, 13B, and 13C are wired while being folded back in a zigzag shape to approximately rectangular electrically insulating sheet-like materials 12A, 12B, and 12C such as mica. It is a type heater.
The heating element elements 11A, 11B, 11C have a wiring density of the heating wires 13A, 13B, 13C in the end regions W1, W1 on both sides compared to the central region W2 in the extending direction W of the sheet-like materials 12A, 12B. Is high.
The width of the heating element elements 11A, 11B, and 11C in the arrangement direction L is such that the heating element element 11B in the central region L2 is relatively wide, and the width of the heating element elements 11A and 11C in the end regions L1 on both sides is relatively wide. It has become narrower. The heating element elements 11A and 11C have the same configuration, and have the same width and wiring density distribution.
The heating plate 10 has a structure in which heating element elements 11A, 11B, and 11C are sandwiched between metal plates 15A and 15B made of stainless alloy or the like from both sides. The metal plates 15A and 15B are joined together at their peripheral edges by welding or the like. The metal plates 15A and 15B forming both sides of the heating plate 10 have a similar temperature distribution.

In this embodiment, a plurality of heating elements are built into the heating plate 10, and the heating wire of each heating element is arranged from one end to the other end in the extending direction W. By changing the width of the heating element elements in the arrangement direction L and changing the wiring density in the extending direction W, the in-plane distribution of the heat generation amount of the heating plate 10 is influenced by the environment in which the heating plate 10 is installed. This makes it possible to respond to external disturbances. In addition to optimizing the in-plane distribution of the calorific value of the heating plate 10 according to environmental disturbances, in combination with the above-described temperature adjustment device 40, high in-plane temperature uniformity of the heating plate 10 can be achieved. Note that the configuration of the heating element of the heating plate 10 is merely an example, and it goes without saying that it can be modified in various ways depending on environmental disturbances.

Each of the heating plates 10 is provided with temperature sensors 14A, 14B made of thermocouples or the like.
The temperature sensor 14A is provided at the center Ct of the heating element 11B in the arrangement direction L, and the temperature sensor 14B is provided approximately at the center of the heating element 11A in one end region L1. Although the number of temperature sensors is not limited to this, it is necessary to provide one heating plate 10 with at least one temperature sensor.
No temperature sensor is provided in the heating element 11C. The heating element 11C is formed laterally symmetrically with the heating element 11A, and has the same size and structure as the heating element 11A. The temperature distribution on the heating element 11C can be estimated from the detected temperature of the heating element 11A. That is, the number of temperature sensors can be reduced by making the arrangement and configuration of the plurality of heating elements symmetrical with respect to the center line of each of the arrangement direction L and the extension direction W.

As shown in FIG. 5, a power cable 16 that supplies current to the heating wires 13A, 13B, 13C is led out from one end surface of the heating plate 10 in the extending direction W, and the power cable 16 is connected to the temperature sensor 14A, 14B. A cable 17 for connecting to the adjustment device 40 is also led out from one end surface of the heating plate 10 in the extending direction W. This is a great advantage since the power cable 16 and cable 17 do not interfere with the heating plates 10 when the heating plates 10 are stacked.

The temperature control device 40 shown in FIG. 1 is electrically connected to the heating wires 13A, 13B, and 13C of each heating plate 10, and independently controls the power supplied to the heating wires 13A, 13B, and 13C. It is possible. Specifically, the temperature adjustment device 40 adjusts the heating element elements of the plurality of heating plates 10 so that the detected temperature of the temperature sensors 14A, 14B provided on each of the plurality of heating plates 10 follows the target temperature. The calorific value of each of 11A, 11B, and 11C is controlled independently.
In temperature adjustment of one heating plate 10, for example, if the temperature in the central region is higher than the target temperature and the temperature in the end regions is lower than the target temperature, the power supplied to the heating wire 13B in the central region L2 is By relatively decreasing the temperature and relatively increasing the power supplied to the heating wires 13A and 13C in both end regions L1, the in-plane temperature distribution of the heating plate 10 can be made uniform regardless of environmental disturbances. .
When a plurality of heating plates 10 are stacked, heat increases from the bottom to the top, so the temperature of the heating plate 10 placed above is higher than that of the heating plate 10 placed below. The temperature adjustment device 40 relatively reduces the amount of heat generated by each of the heating elements 11A, 11B, 11C of the heating plate 10 arranged above, and reduces the heat generation elements 11A, 11B, 11C of the heating plate 10 arranged below. The power supply is controlled so that the heat generation amount of each of the heating plates 11C is relatively increased and the temperature of all the plurality of heating plates 10 is made uniform.
As a result, a large plate-shaped or sheet-shaped object 20 to be heated can be uniformly heated in all the heating spaces 30 of the heating device 1 .

The heating elements 11A, 11B, and 11C built into the heating plate 10 may be, for example, planar heaters or band-shaped heaters described below.
There are two types of planar heaters, depending on the material and shape of the heating wire (heating wire):
1) Wire type (also called double wire type)
Material: Ni-Cr type (nichrome wire), Fe-Cr-Al type (iron chromium wire), Kanthal wire, etc. For example, wire-like heating wire can be wrapped around an insulator or wired by feeding it on the plane of the insulator. This is what I did. In the case of a type in which wire is wound around an insulator, coarse and dense winding is possible by changing the winding pitch. In addition, in the case of a type in which wires are routed through an insulating plane, it is possible to secure an intimate surface by changing the layout of the wires.
2) Band type (also called tape type)
Material: Ni-Cr type (nichrome wire), Fe-Cr-Al type (iron chrome wire), stainless steel type wire, etc. A band-shaped heating wire is wrapped around an insulator, or wired in a planar shape by etching from a sheet. It is something. In the case of a type in which a band is wrapped around an insulating material, intimate winding is possible by changing the winding pitch. In addition, in the case of a type molded by etching, it is possible to realize a coarse and dense surface by changing the pattern layout.

In the above embodiment, the heating element elements 11A, 11B, and 11C are arranged in three regions: the central region W2 where the wiring density of the heating wires 13A, 13B, and 13C is sparse, and the end regions W1 and W1 on both sides where the wiring density is dense. However, it is of course not limited to this, and may be formed in more areas. Further, the number of heating elements constituting the heating plate 10 is not limited to three, but four or more may be formed in line. Furthermore, regarding the wiring density of the heating wires 13A, 13B, and 13C, the density in the end areas W1 on both sides was made gradually higher than in the center area W2 in the width direction. Of course, it is also possible to gradually increase the density.

Although the heating plate 10 of the other embodiment has a planar heater interposed between two metal plates, it is also possible to incorporate a rod-shaped heater into one metal plate.
The heating plate 100 shown in FIGS. 8 to 10 has a plurality of holes 102 arranged in an arrangement direction L in a single substantially rectangular metal plate 101, and these holes are arranged in an extending direction W perpendicular to the arrangement direction L. It extends to Rod-shaped heaters 103 are inserted into the plurality of holes 102, respectively.
The arrangement interval of the rod-shaped heaters 103 in the arrangement direction L changes so as to gradually become narrower from the center Ct to both ends E thereof. The rod-shaped heaters 103 are arranged symmetrically with respect to the center Ct. Note that the plurality of holes 102 are preferably through holes, but need not be through holes, and may be appropriately determined in consideration of the performance of the rod-shaped heater 103 and the like.
As shown in FIG. 10, in the extending direction W of the rod-shaped heater 103, the wiring density of the heating wires 103A of the rod-shaped heater 103 in the end regions W1, W1 on both sides thereof is higher than that in the central region W2. .
In this embodiment, the heating plate 100 has a plurality of rod-shaped heaters 103 as heating elements built into the heating plate 100, and each rod-shaped heater 103 is arranged from one end of the heating plate 100 in the extending direction W to the other end. By changing the arrangement spacing of the heating element elements in the arrangement direction L and changing the wiring density in the extending direction W, the in-plane distribution of the heat generation amount of the heating plate 100 is adjusted from the environment in which the heating plate 100 is installed. This makes it possible to respond to external disturbances. By optimizing the in-plane distribution of the calorific value of the heating plate 100 according to environmental disturbances, and in combination with the above-described temperature adjustment device 40, it is possible to achieve high in-plane temperature uniformity of the heating plate 100.

As shown in FIG. 9, the heating plate 100 is provided with temperature sensors 104A and 104B at the center Ct in the arrangement direction L and at one end. Temperature sensors 104A and 104B may be embedded in heating plate 100 or may be fixed to the surface of heating plate 100. Regarding the wiring density of the heating wire 103A of the rod-shaped heater 103, the density in the end regions W1 on both sides was made gradually higher than in the central region W2, but the density gradually increased from the center in the width direction to both ends. Of course, it's okay to keep it secret.

Here, a specific example of the rod-shaped heater 103 will be explained.
An example of a rod-shaped heater structure is as follows.
1) Bobbin winding type A wire-shaped heating wire is wound around the outer circumference of a magnesium oxide bobbin. According to this, by winding it around a bobbin, it is possible to handle even thin heating wires, allowing a wide capacity range to be set.Since the heating wire can be stably fixed, the entire heater can be drawn, and high-temperature specifications are possible. .
2) Air core type This is a wire-like heating wire molded into a coil shape without a bobbin. According to this, since the heating wire is coiled, the heating wire needs to have mechanical strength to maintain a stable shape after molding, so the range of the heating capacity is small. In both cases, powdered magnesium oxide is interposed between the heating element and the outer cylindrical metal for insulation.

The object to be heated 20 may be a sheet-like object or a plate-like object. The object to be heated 20 is inserted into the heating space 30 by a crane, a robot arm, or the like (not shown). At this time, the left and right guiding members 61L and 61R guide the heated object 20 into the heating space 30 so as not to damage it.

Here, the object to be heated 20 will be explained.
Generally, there are two types of objects to be heated (workpieces):
1) Hard type (also called board type)
It is a strong sheet-like object.
This applies to substrates, plastic plates, glass plates, etc. This type of object to be heated (workpiece) can be placed directly into the furnace and heated. The method of holding in the furnace is such that the holding parts are placed in contact with the object to be heated (workpiece). If it is a board, it indicates that the disposable board part is held. The holding parts include a guide, a pin installed on the upper surface of the heating plate 10, which will be described later. This type of work can also be directly held by the guide members 60L and 60R described above.
2) Soft type (also called sheet type)
It is a soft sheet-like object.
Applicable products include films, foils, and rubber sheets. Due to handling concerns, this type of heated object (workpiece) cannot be placed directly into the furnace, so it is placed in a jig and heated. The holding method in the furnace indicates that the jig is held. The holding parts are the same as in 1) above.

FIG. 12 shows that when the heated object 20 is in the form of a sheet, when the heated object 20 is inserted into the heating space 30, the heated object 20 is placed on the side of the heating element so as not to come into direct contact with the heating plates 10, 100. A plurality of pins 81 are vertically arranged in a row at equal intervals in the longitudinal direction.

In FIG. 13, when the object to be heated 20 is a flexible sheet-like object, the peripheral edge of the object to be heated 20 is fixed to a rectangular frame-shaped jig 82, and the object to be heated 20 is cured. It is designed so that it can be placed into the heating space 30 while being attached to the tool 82.

In FIG. 14, when the object to be heated 20 fixed to the jig 82 as shown in FIG. A plurality of pins 81 are vertically arranged in a row with the longitudinal direction directed toward the front.

In this embodiment, the heating space 30 that accommodates the object to be heated 20 is uniformly heated from above and below by each heating plate 10 as described above, and the inside of each heating space 30 is evenly heated. .

Note that the heating device 1 of this embodiment may further include a gas supply means 90 that supplies an inert gas or a specific gas into the plurality of heating spaces 30 (see FIG. 17). In the gas supply means 90, an ejection nozzle device 92 having a plurality of ejection ports 91 arranged in a horizontal row is disposed at an opening on the back side of each heating space 30. Each jet nozzle device 92 has a box shape extending in the width direction W, and has a plurality of jet ports 91 formed at equal intervals on its surface facing the heating space 30 . Each of the jet nozzle devices 92 is supplied with gas from a gas supply source (not shown) through a supply pipe 93 from the back side thereof. When the gas is supplied, it is evenly distributed left and right within the ejection nozzle device 92, and the gas is evenly ejected from each ejection port 91. The supplied gas can replace the air in the heating space 30 with an inert gas or a specific gas, so the introduction of the inert gas can prevent the oxidation of the object to be heated 20 or prevent the oxidation of the heated object 20 and the introduced specific gas. It is also possible to perform surface treatment on the object to be heated 20 by utilizing this reaction.

The heating device 1 of this embodiment has a configuration in which a plurality of heating plates 10 or 100 installed in the form of a shelf are supported by support plates, and the spaces between the support plates, that is, the front, rear, left, and right sides of the device are open. This makes it easy to put in and take out the heated object 20 from the front and back of the heating device 1, and also makes it possible to take the heated object 20 in and out from the left and right sides of the device, if necessary. Can be done.

When gas is supplied into the heating space 30 from the back of the heating device 1, instead of the left and right support plates 50L and 50R that support the heating plate 10 or 100 at the front and back, the entire side surface is provided on the side of the device, respectively. Installing one covering side support plate 83L, 83R can confine the gas within the heating space 30 (see FIGS. 15-18).

In this embodiment, the guide member 60 is used as an example to hold the object to be heated 20, but the guide member 60 is not limited to this. , 50R, it is also possible to form holding grooves directly on the support plates 50L, 50R, and to make the support plates 50L, 50R hold the object to be heated 20.

The heating device according to the present invention can be widely used in the industrial field where various plate-like members and sheet-like members, such as glass substrates, semiconductor lead frames, other metal plates, and synthetic resin plates, are heat-treated.

1 Heating device 10 Heating plate 11A, 11B, 11C Heating element 12A, 12B, 12C Sheet material 13A, 13B, 13C Heat generating wire 14A, 14B Temperature sensor 15A, 15B Metal plate 16 Power cable 17 Cable 20 Heated object 30 Heating space 40 Temperature adjustment device 50L, 50R Support plate 51 Groove 60L, 60R Guide member 61L, 61R Guide member 71 Top plate 72 Bottom plate 73L, 73R Leg member 74 Middle plate 75L, 75R Leg member 76 Base 81 Pin 82 Jig 83L , 83R side support plate 90 gas supply means 91 jet nozzle 92 jet nozzle device 93 supply pipe 100 heating plate 101 metal plate 102 hole 103 rod-shaped heater 103A heating wire 104A, 104B temperature sensor W extending direction L arrangement direction

Claims (8)

at least three or more heating plates arranged at predetermined intervals in the vertical direction;
a heating space for accommodating an object to be heated, defined by heating surfaces of the heating plates facing each other in the vertical direction;
The heating spaces adjacent in the vertical direction are separated by the heating plate,
Each of the heating plates is
A rectangular metal plate,
a plurality of heating element elements built into the metal plate and wired with heating wires;
The plurality of heating element elements are arranged in a first direction of the metal plate and each extend in a second direction orthogonal to the first direction,
The plurality of heating element elements have varying widths or varying arrangement intervals in the first direction,
In the second direction, each of the plurality of heating element elements has a wiring density of the heating wire changing,
a temperature sensor provided on each of the plurality of heating plates;
temperature control means for independently controlling the amount of heat generated by each of the plurality of heating elements of the plurality of heating plates so that the detected temperature of a temperature sensor provided on each of the plurality of heating plates follows a target temperature; , further having
The temperature control means relatively reduces the amount of heat generated by each of the plurality of heating elements of the heating plate arranged above, and reduces the amount of heat generated by each of the plurality of heating elements of the heating plate arranged below. A heating device that controls the relative increase of In each of the plurality of heating element elements, the wiring density of the heating wires in both end regions is higher in the second direction than in the central region,
The heating device according to claim 1, wherein the plurality of heating element elements have narrower widths in both end regions than in a central region in the first direction. In each of the plurality of heating element elements, the wiring density of the heating wires in both end regions is higher in the second direction than in the central region,
2. The heating device according to claim 1, wherein the plurality of heating element elements have narrower arrangement intervals in both end regions than in the central region in the first direction. The heating device according to any one of claims 1 to 3 , wherein at least one of the four sides of each of the heating spaces is open. 5. The heating device according to claim 4 , wherein each of the heating spaces has openings on all four sides. Any one of claims 1 to 5, wherein a power supply cable that supplies power to each of the plurality of heating elements of the plurality of heating plates is led out from one end of the plurality of heating plates in the second direction. The heating device described in . The heating device according to any one of claims 1 to 6, further comprising a gas supply means for supplying an inert gas or a specific gas from one opening of the heating space to another opening opposite to this opening. . A heating plate used in the heating device according to any one of claims 1 to 7 .

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