JP2001012871A - Double heating thermostat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double heating thermostat formed such that a product defect due to a solvent component hardly occurs when a plate-form object to be heated having a surface coated layer is thermally treated. SOLUTION: Hot air is circulated through a gap between an external chamber 2 and an internal chamber 1 by a hot air circulation device 4, and the internal chamber 1 is uniformly heated from the whole of an outer periphery. Since the internal part of the internal chamber 1 is held at a constant temperature by a radiant heat, a solvent component is prevented from remaining in the surface coated film of a plate-form object A to be heated and vapor condensation is prevented from occurring in the internal chamber 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double heating constant temperature bath for heat treating a plate-like product such as a glass substrate used in an LCD manufacturing process.

[0002]

2. Description of the Related Art As a heat treatment furnace for heat treatment of a plate-shaped object to be heated, for example, as disclosed in Japanese Utility Model Laid-Open No. 5-9639, a hot air circulation type double heating constant temperature bath is used.
The double heating constant temperature bath has a structure in which a hot plate, which is a plate-like heating element, is provided inside the constant temperature bath, and an object to be heated is placed on the hot plate with its plate surface in close contact with the hot plate. The hot plate uniformly transfers heat to the plate surface of the plate-like heated object, and the constant temperature bath is for maintaining the temperature around the plate-like heated object uniformly. In particular, the double temperature bath is provided with a heater as a second heating device in the gap between the outer bath and the inner bath, and the air heated by this heater is supplied to the above-mentioned fan using the fan provided in the gap. The furnace is forced to circulate between the gap and the inside of the inner tank to keep the furnace temperature more uniform (for example, see Japanese Utility Model Laid-Open No. 5-9639).

[0003]

In the above-mentioned double heating constant temperature bath, when the plate-shaped object to be heated has a surface coating layer such as an alignment film of an LCD, when heated by a hot plate, The solvent component evaporates from the surface coating layer. At this time, since the surface of the coating layer is hardened faster than the inside by the circulating hot air, there is a problem that a solvent component remains in the film and a product defect occurs. When heat treatment is performed only with a hot plate in order to prevent such a problem from occurring, the evaporated solvent component condenses at the low temperature part of the heating chamber and remains in the heating chamber,
There is a problem that causes product defects. In view of the conventional problems as described above, the present invention provides a dual heating constant temperature bath in which a product defect due to a solvent component is not easily generated when a plate-like heated object having a surface coating layer is heat-treated. The purpose is to:

[0004]

According to the present invention, there is provided a dual-heating constant-temperature bath for achieving the above object. The double-heating constant-temperature bath is accommodated in the outer chamber with a gap provided all around the outer chamber. An internal chamber in which ventilation from the inside to the inside is blocked, a first heating device including a hot plate provided in the internal chamber, and a second heating device that heats the internal chamber from the surroundings and maintains a constant temperature. It is characterized by having. According to the double heating constant temperature bath having the above configuration, ventilation from the gap into the internal chamber is prevented, so that the air warmed by the second heating device hits the surface of the plate-shaped object to be heated, The surface of the object to be heated is not hardened faster than the inside. In addition, a gap is provided over the entire circumference between the outer chamber and the inner chamber, and the air layer in the gap is heated by a heating device, so that the inner chamber is uniformly kept warm without generating a low-temperature portion. You. For this reason, it is possible to prevent dew condensation from occurring on the inner wall of the inner chamber.

It is preferable that the second heating device is a hot air circulating device for circulating hot air in a gap between the internal chamber and the external chamber. In this case, since the hot air can be brought into contact with the outer periphery of the internal chamber all over, the entire internal chamber can be more uniformly kept warm.

The internal chamber preferably has an exhaust hole for exhausting gas inside the external chamber to the outside of the external chamber. In this case, the gas in the internal chamber can be exhausted to the outside of the external chamber through the exhaust hole, so that the gas can be prevented from staying in the internal chamber. Therefore, the gas concentration in the internal chamber can be maintained at a low level.

[0007]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing one embodiment of a double heating constant temperature bath of the present invention. The double heating constant temperature bath according to the present invention includes a hot plate 3 as a first heating device for heating the plate-like object A to be heated.
An internal chamber 1 for providing a hot plate 3 therein and keeping the entire interior warm with radiant heat;
And a hot air circulating device 4 (second heating device) for circulating hot air through the gap between the internal chamber 1 and the external chamber 2.

[0008] The external chamber 2 comprises an upper housing 21 and a lower housing 22 which are constituted by heat insulating walls. The upper housing 21 can be lifted to open the outer chamber 2, and can be placed on the lower housing 22 to seal the outer chamber 2. The upper housing 21 and the lower housing 2
2, a hot air supply hole 2a for introducing hot air.
And a hot-air discharge hole 2b for discharging the hot-air circulating device 4 are connected to the hot-air circulating device 4 installed outside the external chamber 2 via a pipe.

The internal chamber 1 is made of a material having good thermal conductivity, and is divided into an upper lid 11 which is lifted up to open the internal chamber 1 and a storage section 12 which stores the plate-like object A to be heated. Have been. The internal chamber 1
Is held at a hollow position in the external chamber 2 by the support portion 13 so that a gap can be formed over the entire circumference with the external chamber 2. For this reason, the hot air supplied by the hot air circulation device 4 circulates all around the internal chamber 1, and
Heat the whole evenly.

The hot plate 3 is provided at a central portion inside the internal chamber 1. Further, an air supply hole 1 for introducing air is provided in an upper portion of a wall surface of the internal chamber 1.
a is provided, and exhaust holes 1 b for exhausting gas in the internal chamber 1 are provided at two lower portions of the wall surface. The air supply hole 1a and the air exhaust hole 1b are connected to a pipe (not shown) and directly connected to an air supply / exhaust device (not shown) provided outside the external chamber 2. For this reason,
The evaporated solvent component is carried to the air supply / exhaust equipment (not shown) outside the external chamber 2 by the air passing through the path b.

According to the above configuration, the hot air blown into the inside of the external chamber 2 from the hot air supply hole 2a of the external chamber 2 by the hot air circulating device 4 is a hot air circulation path in a gap between the external chamber 2 and the internal chamber 1. The air is discharged from the hot-air discharge hole 2b via a. The internal chamber 1 is heated by the hot air. Since the inside of the internal chamber 1 is prevented from entering the hot air from the gap, the plate-like heating target A is heated in this state by maintaining a uniform temperature as a whole by radiant heat from the wall surface. For this reason, the plate-shaped object A to be heated from below by the heat transfer from the hot plate 3 is not directly hit by the hot air, and the upper surface does not harden faster than the inside. Furthermore, since the entire internal chamber 1 is uniformly heated by the hot air circulating device 4 and no partial low-temperature portion is generated on the inner wall of the internal chamber 1, the evaporated solvent component does not condense again on the inner wall of the internal chamber 1. . Further, since the gas in the internal chamber 1 is exhausted to the outside through the exhaust hole 1b, it does not concentrate in the internal chamber 1.

In the above embodiment, the internal chamber 1 is heated by using the hot air circulating device 4. However, the internal chamber 1 may be heated by a tape heater, a heating lamp, or the like capable of maintaining a temperature at which the solvent component evaporates. The same effect is obtained.

[0013]

As described above, according to the double heating constant temperature bath according to the first aspect, the surface of the coating film cures faster than the inside and the solvent component remains in the film, No solvent condensation occurs. For this reason, for example, the orientation film of the LCD is unlikely to cause a product defect due to the solvent, so that the yield can be improved.

According to the double heating constant temperature bath according to claim 2,
Since hot air is brought into contact with the outer periphery of the internal chamber all over, and the internal chamber can be kept at a more uniform temperature distribution, the reliability of the heat treatment can be improved.

According to the double heating constant temperature bath according to claim 3,
Since the solvent concentration in the internal chamber can be maintained at a low level, the yield can be further improved. Further, the gas in the internal chamber does not flow into the gap between the internal chamber and the external chamber, so that maintenance is easy.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a dual heating constant temperature bath according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 internal chamber 1a air supply hole 1b exhaust hole 2 external chamber 2a hot air supply hole 2b hot air discharge hole 3 hot plate (first heating device) 4 hot air circulation device (second heating device) A plate-shaped object to be heated

Claims (3)

[Claims] 1. An external chamber, an internal chamber which is housed inside the external chamber with a gap provided over the entire circumference thereof, and wherein ventilation from the gap to the inside is prevented, and a hot chamber provided in the internal chamber. A double-heating constant-temperature bath comprising: a first heating device formed of a plate; and a second heating device that heats the internal chamber from the surroundings and maintains the temperature at a constant temperature. 2. The double heating constant temperature bath according to claim 1, wherein the second heating device is a hot air circulation device for circulating hot air in a gap between the inner chamber and the outer chamber. 3. The double heating constant temperature bath according to claim 1, wherein the internal chamber has an exhaust hole for exhausting gas inside the external chamber to the outside of the external chamber.