JP4530896B2 - Plate type far infrared heater for vacuum heating furnace - Google Patents

Description

  The present invention relates to a plate-type far infrared heater for a vacuum heating furnace used in a vacuum heating furnace.

2. Description of the Related Art A plate-like plate type far infrared heater that emits far infrared rays from one surface toward a heated object in order to heat the heated object in a vacuum heating furnace is known. For example, the plate-shaped heating device (22) described in Patent Document 1 is that. According to the vacuum heating furnace provided with such a plate heating device, a plurality of plate heating devices are provided between the plurality of substrates supported by the support so as to be parallel to the substrates. And when temperature control is performed so that the respective temperatures are equal in the plurality of plate-like heating devices, radiation of far infrared rays from the plate-like heating device in the high vacuum space formed in the furnace body, Without using heat conduction or convection, uniform heat treatment is simultaneously performed on a plurality of substrates in one batch.
JP 2004-37044 A

  Usually, the plate heating device includes a metal plate made of stainless steel or aluminum alloy, a rod heater embedded in the metal plate, and a far infrared radiation layer fixed to the surface of the metal plate. The far infrared rays of energy corresponding to the heating temperature by the rod-shaped heater are radiated from the far infrared radiation layer on the surface of the metal plate.

  By the way, in the said conventional vacuum heating furnace, since it is requested | required to increase the number of the board | substrates which can be accommodated in 1 batch as much as possible, while forming a plate-shaped heating apparatus thinly, for example, 300 A relatively high uniform heating performance at a relatively high temperature of about ˜450 ° C. may be required. In such a case, in order to improve uniform heating performance, it is necessary to use an aluminum-based metal having a high thermal conductivity. However, when used at such a relatively high temperature, the metal is softened and the metal plate is used. There is a problem that deformation of the plate heating device occurs in combination with the reduction in thickness.

  The present invention has been made against the background of the above circumstances, and the object of the present invention is to provide a plate type for a vacuum heating furnace that can be configured to be thin and can be uniformly heated at a relatively high temperature without deformation. It is to provide a far infrared heater.

The invention according to claim 1 for achieving such an object is a plate type far-infrared heater for a vacuum heating furnace used in a vacuum heating furnace, comprising: (a) a far-infrared radiation film fixed on one surface and a rod-like shape; An aluminum heater main body having a predetermined thickness in which the heater is embedded; (b) a reinforcing plate disposed on the other surface of the heater main body and made of a material stronger than the heater main body; and (c) the reinforcement. A fixing device for fixing the plate and the heater body in close contact with each other while allowing a deviation in the plane direction due to a difference in thermal expansion between each other, and (d) formed in the heater body so as to penetrate in the longitudinal direction. A plurality of through holes formed, (e) a first air cooling pipe and a second air cooling pipe respectively connected to both ends of the plurality of through holes, and (f) an object to be heated is cooled from the heat treatment temperature. In the cooling section, the first air cooling pipe and the second air cooling A first position for supplying cooling air to one of the pipes and simultaneously exhausting the other air; and a second position for supplying cooling air to the other of the first air cooling pipe and the second air cooling pipe and simultaneously exhausting one of the air And a switching valve device that can be switched alternately .

  The plate type far-infrared heater for vacuum heating furnace of the invention according to claim 2 is characterized in that the heater body is made of pure aluminum.

  According to a third aspect of the present invention, there is provided a plate-type far-infrared heater for a vacuum heating furnace, wherein the rod heater includes a metal outer cylinder, a heating element supported by insulating powder in the outer cylinder, and one end. The part is inserted into the outer cylinder and connected to the heating element, and the other end is fixed between the outer peripheral surface of the connection terminal and the inner peripheral surface of the outer cylinder. And a sealing material that hermetically seals the inside of the outer cylinder.

  The plate-type far-infrared heater for a vacuum heating furnace according to the fourth aspect of the invention is arranged such that the heating element of the rod-shaped heater increases in density from the center to the end of the outer cylinder. It is a saddle-type wire rod.

According to the plate-type far-infrared heater for a vacuum heating furnace of the invention according to claim 1, (a) an aluminum heater body having a predetermined thickness in which a far-infrared radiation film is fixed on one surface and a rod-shaped heater is embedded, The fixing device is fixed to the reinforcing plate in close contact with each other while allowing deviations in the plane direction due to the difference in thermal expansion between each other, and (b) a plurality of pieces formed through the heater body in the longitudinal direction. A through hole; and (c) a first air cooling pipe and a second air cooling pipe respectively connected to both ends of the plurality of through holes, and (d) in a cooling section where the heated object is cooled from the heat treatment temperature. A first position for supplying cooling air to one of the first air-cooling pipe and the second air-cooling pipe and simultaneously exhausting the other air, and simultaneously supplying cooling air to the other of the first air-cooling pipe and the second air-cooling pipe Second place to exhaust air Since the overall strength is increased even if the thickness of the heater body is reduced, it can be heated uniformly without deformation even at relatively high temperatures. A plate type far infrared heater is obtained. Further, the temperature in the plate type far infrared heater in the cooling section is made uniform.

  Further, according to the plate type far infrared heater for vacuum heating furnace of the invention according to claim 2, since the heater main body is made of pure aluminum, the heater main body can be removed from the heater main body even under a relatively high vacuum in the vacuum heating furnace. Generation of gas is suppressed and the quality of vacuum heating is improved.

  The plate-type far-infrared heater for a vacuum heating furnace of the invention according to claim 3 includes a rod-shaped heater, a metal outer cylinder, a heating element supported by insulating powder in the outer cylinder, and one end The part is inserted into the outer cylinder and connected to the heating element, and the other end is fixed between the outer peripheral surface of the connection terminal and the inner peripheral surface of the outer cylinder. And a sealing material that hermetically seals the inside of the outer cylinder, so that gas generated from insulating powder such as magnesium oxide is sealed under a relatively high vacuum in a vacuum heating furnace. Since it is sealed in the outer cylinder by the stopper, the quality of vacuum heating is improved.

  The plate-type far-infrared heater for a vacuum heating furnace according to the fourth aspect of the invention is arranged such that the heating element of the rod-shaped heater increases in density from the center to the end of the outer cylinder. In addition, since it is a saddle type wire, the temperature in the heater or on the surface is made more uniform, so that the uniform heating performance is enhanced.

  Here, preferably, the fixing device for fixing the heater main body to the reinforcing plate in a close contact state while allowing a deviation in the surface direction due to a difference in thermal expansion between the heater main body and the heater main body and the reinforcing plate is in an intimate contact state. It is only necessary to support the bolts and rivets so that they can be moved relative to each other while holding the bolts. Alternatively, the rivet may be provided with a long hole or an engaging groove that allows relative movement in the surface direction with respect to one of the heater body and the reinforcing plate.

  The reinforcing plate may be a heat-resistant and high-strength metal material, and may be not only a well-known stainless steel plate but also a high-strength ceramic plate.

The far-infrared radiation film fixed to one surface of the heater main body is a well-known far-infrared radiation material such as inorganic powder bonded with a binder such as glass. As the far infrared radiation material, silica (SiO ₂ ), zirconium oxide (ZrO ₂ ), tin oxide (SnO ₂ ), titanium oxide (TiO ₂ ), alumina (Al ₂ O ₃ ), beryllia (BeO ₂ ), cordier light _{(2MgO · 2Al 2 O 3 ·} 5SiO 2) II~IV group metals oxide ceramics such as iron oxide _{(Fe 2 O} 3), chromium oxide _{(Cr 2 O} 3), nickel oxide (NiO), cobalt oxide Group II-VIII metal oxide ceramics such as (CoO), non-oxide ceramics such as silicon carbide (SiC), and mixtures thereof are preferably used.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a front sectional view for explaining the configuration of a vacuum heating furnace 12 provided with a plate-type far infrared heater 10 according to an embodiment of the present invention. In FIG. 1, a vacuum heating furnace 12 includes a furnace wall 16 for forming a vacuum heating space 14 that is evacuated by a vacuum pump (not shown), and is housed in the furnace wall 16, and an electric cylinder or the like is moved up and down. A lifting shelf 20 that is moved up and down by the device 18 is provided. The elevating shelf 20 is arranged so as to sandwich the elevating shelf 20 between a pair of supporting walls 22, a plurality of (six in this embodiment) shelf plates 24 spanned between the supporting walls 22. In addition, a plurality of plate-type far infrared heaters 10 whose both ends are supported by the support wall 22 are provided. A substrate 28 is supported on the shelf plate 24 via a support member 26 that is supported in a small area, and the substrate 28 is supported by far infrared rays from the plate-type far infrared heater 10 positioned facing the substrate 28. It is supposed to be heated.

  The substrate 28 is a glass substrate used for a flat display panel such as a liquid crystal display panel (LCD), a plasma display panel (PDP), an organic EL display panel, etc., and a high density wiring or the like is formed on the surface thereof in a predetermined pattern. In order to arrange the wiring material, a wiring material applied in a predetermined pattern by printing or the like is fixed by heat treatment under vacuum in the vacuum heating furnace 12. This heat treatment is shown, for example, in the heat curve of FIG. 2, and is heated to a heat treatment temperature, eg, 440 ± 5 ° C., at a predetermined speed set in advance and held at the heat treatment temperature for a predetermined time, eg, about 120 minutes. Then, it is cooled at a predetermined speed set in advance. At this time, in order to prevent distortion, it is important that the temperature of each part of the substrate 28 is a uniform temperature within several degrees Celsius as the size of the substrate 28 increases. FIG. 2 shows a line indicating the minimum temperature and a line indicating the maximum temperature in one substrate 28, and the temperature of each part of the substrate 28 is within the width.

  3 is a front view showing the plate-type far-infrared heater 10 from the radiation surface side, FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, and FIG. 5 is a sectional view taken along line V-V in FIG. is there. As shown in FIGS. 3 to 5, the plate-type far-infrared heater 10 has a rectangular plate shape having a predetermined thickness, for example, a thickness of about 15 mm, with a far-infrared radiation film 30 fixed to one surface and a rod-shaped heater 32 embedded therein. The heater main body 34 made of pure aluminum and a rectangular plate having a predetermined thickness, for example, a thickness of about 5 mm, are formed on the other surface of the heater main body 34 and are made of a material having higher strength than the heater main body 34, such as a stainless steel plate. And a fixing device 38 for fixing the reinforcing plate 36 and the heater main body 34 in close contact with each other while allowing a displacement in the surface direction due to a difference in thermal expansion between the reinforcing plate 36 and the heater main body 34. As shown in FIG. 1, the plate-type far infrared heater 10 has both ends supported by the support wall 22 with the reinforcing plate 36 on the lower side and the heater body 34 on the upper side. Far-infrared rays are emitted from the lower side.

  The far-infrared radiation film 30 includes well-known far-infrared radiation materials such as II-IV group metal oxide ceramics, II-VIII metal oxide ceramics, non-oxide ceramics, and mixtures thereof, that is, inorganic powders. The body is bonded to one surface or surface of the heater body 34 by melting or spraying a binder such as glass. Therefore, a reinforcing plate 36 that reinforces the heater body 34 is attached to the back surface of the heater body 34.

  The rod-like heater 32 has a longitudinal shape with a circular cross section, and is penetrated through a through-hole 37 provided in the longitudinal direction of the heater main body 34 so that both ends thereof are exposed. As shown in detail in FIG. 6, the rod heater 32 is supported in an electrically insulated state with respect to the outer cylinder 40 by a metal outer cylinder 40 and an insulating powder 41 such as magnesium oxide in the outer cylinder 40. The spirally wound heating element 42, one end of which is inserted into the outer cylinder and connected to the end of the heating element 42, and the other end of the connecting terminal 44 protrudes from the outer cylinder 40. A sealing material 46 that is fixed between the outer peripheral surface of the connection terminal 44 and the inner peripheral surface of the outer cylinder 40 and hermetically seals the inside of the outer cylinder 44, and the connection terminal 44 and the outer cylinder 40. And an insulator 48 for insulating the gap. For example, the sealing material 46 is obtained by melting a sealing glass whose thermal expansion coefficient is adjusted. A plurality of nuts 50, 52, 54 are screwed to the exposed end of the connection terminal 44, and a bus 56 for supplying a drive current is fixed by the nuts 50, 52, 54. The ring 58 is fixed to prevent the rod-shaped heater 32 from moving in the longitudinal direction.

  The heating element 42 is, for example, a spirally wound nichrome wire, and is disposed so that the winding density increases from the center to the end of the outer cylinder 40 as shown in detail in FIG. Is. As a result, higher thermal energy is applied to the end edge portion of the heater body 34, where the temperature tends to be lower than the center portion, so that the temperature distribution of the heater body 34 is uniform. It has become.

  4 and 5, the fixing device 38 has two types of mounting holes 60 and 62 provided through the heater main body 34 in the thickness direction, and the reinforcing plate 36 through the mounting holes 60 and 62, respectively. A plurality of bolted bolts 64 and a circular collar 66 fitted to the bolts 64 for determining the tightening position of the bolts 64 are provided. The tubular collar 66 has a length slightly shorter than the thickness of the heater main body 34, and when the bolt 64 is tightened, the heater main body 34 and the reinforcing plate 36 are in the surface direction due to the difference in thermal expansion. It is made to contact | adhere with the predetermined | prescribed surface pressure which can be relatively moved. The mounting hole 60 and the mounting hole 62 are spaced apart from each other in the longitudinal direction of the heater body 34. The mounting hole 60 has a circular cross section, whereas the mounting hole 62 has an elliptical cross section (an oblong hole). The space 68 between the inner wall surface of the mounting hole 62 and the bolt 64 allows relative movement in the surface direction due to the difference in thermal expansion.

  As shown in FIGS. 4 and 8, the bar heaters 32 are inserted into every other one of the plurality of through holes 37 provided in the heater body 34, and the bar heaters 32 are not inserted. The hole 37 is used for passing cooling air. In FIG. 8, the rod heater 32 is omitted. As shown in detail in FIG. 8, a first air cooling pipe 70 and a second air cooling pipe are provided at both ends of a plurality of through holes 37 penetrating the heater main body 34 in the longitudinal direction where the rod-like heater 32 is not fitted. 72 are connected to each other. The first air cooling pipe 70 and the second air cooling pipe 72 are connected to the first output port 76 and the second output port 78 of the switching valve device 74, respectively. In the vacuum heating furnace 12, the cooling air amount is controlled by a temperature control device (not shown) so that the temperature is lowered at a constant change rate in the cooling section where the substrate 28 is cooled from the heat treatment temperature, and the switching valve device 74. 8 supplies the cooling air supplied from the cooling air supply source 80 to the first air cooling pipe 70 and at the same time exhausts the air in the second air cooling pipe 72, and supplies the cooling air from the cooling air supply source 80. The cooling air to be supplied is supplied to the second air-cooling pipe 72, and at the same time, the plate-type far infrared heater 10 in the cooling section is alternately positioned at a second position where the air in the first air-cooling pipe 70 is exhausted. The temperature distribution inside is made uniform.

  As described above, according to the present embodiment, the plate-type far infrared heater 10 for the vacuum heating furnace 12 has a predetermined thickness in which the far infrared radiation film 30 is fixed to one surface and the rod heater 32 is embedded. The heater main body 34 made of aluminum is fixed to the reinforcing plate 36 in close contact with each other while allowing the displacement in the surface direction due to the difference in thermal expansion between the two by the fixing device 38, so that the thickness of the heater main body 34 is reduced. However, since the strength as a whole is increased, uniform heating can be performed without deformation even at a relatively high temperature.

  Further, according to the plate type far infrared heater 10 of the present embodiment, since the heater body 34 is made of pure aluminum, gas is generated from the heater body 34 even under a relatively high vacuum in the vacuum heating furnace 12. Is suppressed, and the quality of vacuum heating is improved.

  Further, the plate-type far infrared heater 10 of this embodiment includes a rod-shaped heater 32 having a metal outer cylinder 40, a heating element 42 supported by an insulating powder 41 in the outer cylinder 40, and one end portion. Is inserted into the outer cylinder and connected to the heating element 42, and the other end protrudes from the outer cylinder, and between the outer peripheral surface of the connection terminal 44 and the inner peripheral surface of the outer cylinder. Since it is provided with a sealing material 46 that is firmly fixed and hermetically seals the inside of the outer cylinder, it is generated from the insulating powder 41 such as magnesium oxide under a relatively high vacuum in the vacuum heating furnace 12. Since the gas to be sealed is sealed in the outer cylinder by the sealing material, the quality of vacuum heating is improved.

  The plate-type far-infrared heater 10 of the present embodiment is also provided with a wire-type wire rod in which the heating element of the rod-shaped heater 32 is arranged so that the wire density increases from the center portion to the end portion of the outer cylinder. (Nichrome wire), the temperature in the plate-type far infrared heater 10 or on the surface is made more uniform, so that the uniform heating performance is enhanced.

  The plate-type far-infrared heater 10 of this embodiment is supported by the support wall 22 at both ends thereof with the reinforcing plate 36 on the lower side and the heater body 34 on the upper side. Since far infrared rays are emitted from the lower side, even if the heater main body 34 is softened, generation of a gap between the heater main body 34 and the reinforcing plate 36 is suitably prevented.

  In the vacuum heating furnace 12 of the present embodiment, the amount of cooling air is controlled by a temperature control device (not shown) so that the temperature is lowered at a constant change rate in the cooling section in which the substrate 28 is cooled from the heat treatment temperature. The switching valve device 74 supplies the cooling air supplied from the cooling air supply source 80 to the first air-cooling pipe 70 and simultaneously exhausts the air in the second air-cooling pipe 72, as shown in FIG. Since the cooling air supplied from the air supply source 80 is supplied to the second air-cooling pipe 72 and at the same time the second position for exhausting the air in the first air-cooling pipe 70 is alternately positioned at a predetermined cycle, the heater body 34 In the through-hole 37, cooling air is flowed bidirectionally at a predetermined cycle, and the temperature distribution in the plate type far-infrared heater 10 in the cooling section is made uniform.

  As mentioned above, although this invention was demonstrated in detail with reference to drawings, this invention can be implemented also in another aspect.

  For example, the shape of the heater main body 34 and the rod-shaped heater 32 embedded in the heater body 34 can be variously different depending on the shape of the vacuum heating furnace 12, the shape of the substrate 28, and the like.

  The plate type far-infrared heater 10 described above has both ends supported by the support walls 22 with the heater body 34 positioned on the upper side and the reinforcing plate 36 positioned on the lower side. The heater structure 34 may not be a support structure, and the heater main body 34 may be disposed with the reinforcing plate 36 positioned on the lower side, or the center portion of the plate-type far-infrared heater 10 may be supported.

  The plate-type far-infrared heater 10 described above has a two-layer structure including a heater body 34 and a reinforcing plate 36 that supports the heater body 34 from the back side. The heater body 34 is attached to both surfaces of the reinforcing plate 36. A three-layer structure may be used.

  The above description is merely an example of the present invention, and the present invention can be variously modified within the scope of the knowledge of those skilled in the art without departing from the spirit of the present invention.

It is front sectional drawing explaining the structure of the vacuum heating furnace provided with the plate type far-infrared heater of one Example of this invention. It is a figure which shows an example of a heat curve when a board | substrate is heated with the vacuum heating furnace of FIG. It is a front view which shows the plate type far-infrared heater of FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3 for explaining the configuration of the plate-type far infrared heater in FIG. 1. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 3 for explaining the configuration of the plate-type far-infrared heater in FIG. 1. FIG. 2 is a cross-sectional view of a main part cut out in a state of being attached to the plate-type far-infrared heater in order to explain the configuration of a rod-shaped heater used in the plate-type far-infrared heater of FIG. 1. It is sectional drawing which shows the winding state of the heat generating body in the rod-shaped heater used for the plate type far-infrared heater of FIG. FIG. 2 is a diagram schematically illustrating a configuration of an air cooling device provided in a plate type far infrared heater in order to cool at a predetermined speed and make temperature distribution uniform in a substrate cooling section in the vacuum heating furnace of FIG. 1.

Explanation of symbols

10: Plate type far infrared heater 12: Vacuum heating furnace 32: Bar heater 34: Heater body 36: Reinforcing plate 38: Fixing device 40: Outer cylinder 42: Heating element 44: Connection terminal 46: Sealing material

Claims (4)

A plate type far infrared heater for a vacuum heating furnace used in a vacuum heating furnace,
A heater body made of aluminum having a predetermined thickness in which a far-infrared radiation film is fixed on one surface and a bar heater is embedded;
A reinforcing plate disposed on the other surface of the heater body and made of a material having a higher strength than the heater body;
A fixing device for fixing the reinforcing plate and the heater body in close contact with each other while allowing a deviation in a surface direction due to a difference in thermal expansion between each other;
A plurality of through holes formed through the heater body in the longitudinal direction; and
A first air cooling pipe and a second air cooling pipe respectively connected to both ends of the plurality of through holes;
In a cooling section in which the object to be heated is cooled from the heat treatment temperature, a first position for supplying cooling air to one of the first air cooling pipe and the second air cooling pipe and simultaneously exhausting the other air, and the first air cooling pipe and second position and the switching valve device is switched alternately, vacuum furnace plate type far infrared you comprising evacuating the to simultaneously one air supplying cooling air to the other of the second air pipe heater.   The plate-type far-infrared heater for a vacuum heating furnace according to claim 1, wherein the heater body is made of pure aluminum.   The bar heater includes a metal outer cylinder, a heating element supported by insulating powder in the outer cylinder, one end portion inserted into the outer cylinder and connected to the heating element, and the other end section A connection terminal protruding from the outer cylinder, and a sealing member that is fixed between the outer peripheral surface of the connection terminal and the inner peripheral surface of the outer cylinder and hermetically seals the inside of the outer cylinder The plate type far infrared heater for a vacuum heating furnace according to claim 1 or 2.   The plate-type far-infrared heater for a vacuum heating furnace according to claim 3, wherein the heating element is a wire-type wire disposed such that the wire density increases from the center to the end of the outer cylinder.

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