JP3474087B2 - Heat treatment equipment for uniformly heating flat workpieces - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention heats and heats a flat article placed in the direction from the inlet to the outlet in a heat treatment section having an inlet and an outlet through which heated gas is heated by the gas. The present invention relates to a heat treatment apparatus, and in particular, it is effectively used for a heat treatment apparatus incorporated in a baking process capable of hot air heating such as post-baking of an alignment film or a color filter in a production facility such as an LCD (liquid crystal display) glass substrate.

[0002]

2. Description of the Related Art Conventionally, as a heat treatment apparatus for LCD glass substrates, an air circulation heating type apparatus (for example, JP-A-6-3) is used.
17514) and a hot plate heating type device (see, for example, Japanese Patent Application Laid-Open No. 6-97269). In the air circulation type heat treatment apparatus, hot air controlled to a predetermined temperature is flown in one direction parallel to the glass surface.
As a result, the temperature rise of the glass plate becomes faster in the windward and slower in the leeward, and the temperature distribution generated in the glass plate gives variations in the firing quality. In this case, if the glass plate had a conventional size, the temperature difference between the glass plate on the windward side and the glass plate on the leeward side was relatively small, and variations in firing quality were within an allowable range.

However, recently, in order to increase the screen size of a liquid crystal display and reduce the cost, there is a tendency to increase the size of mother glass in order to enable a large number of screens at one time.
Technical development of large-sized mother glass that exceeds 1 meter square is also underway. When a large-sized glass plate exceeding 1 meter square is thus fired, even if the temperature rises on the windward side and reaches a predetermined temperature to be heat-treated, the temperature on the leeward side becomes several tens of degrees lower than the predetermined temperature. Temperature rise delay occurs,
The variation in firing quality exceeds the allowable limit.

As a method for reducing such a temperature difference, it is considered that the air velocity of the hot air flowing on the glass surface is increased to increase the air volume. However, if the wind speed of the hot air is increased to a certain level or higher, the photosensitive resin pattern or the like formed on the glass surface may be adversely affected. In addition, there is a problem that the size of the device is increased and the cost is increased. In other words, since clean air without dust is required as the air to be supplied to the glass, the air is passed through a high-performance filter that uses a filter medium with a large resistance, so if the wind speed is increased, it is necessary to increase the wind pressure of the blower. There is.

Further, in such a filter, the maximum passing wind speed of the filter medium is determined from the filtering performance. Therefore, in order to increase the air volume by increasing the air volume, the area of the filter medium, and hence the size of the high-performance filter, and the blower It is necessary to increase the capacity. Further, in such a filter, the wind after passing becomes a laminar flow and then flows in parallel to the glass surface, that is, the heat transfer surface, so that the heat exchange efficiency is not good.

On the other hand, in the hot plate heating type device,
In order to improve the temperature distribution of the glass during heat treatment, it is necessary to maintain the temperature distribution of the plate at a sufficiently small value,
When the glass size becomes large, it becomes extremely difficult to maintain such temperature distribution, and it is necessary to perform surface processing with extremely high accuracy, which makes the apparatus expensive. Further, in the hot plate heating method, since the plate and the glass are brought close to each other so that they are almost in contact with each other, it is difficult to prevent destruction of the substrate circuit on the glass due to electrification in the large size glass.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above problems in the prior art, improves heat exchange efficiency without increasing the size of the components of the apparatus and increasing the cost, and improves the flat article shape. It is an object of the present invention to provide a heat treatment apparatus which makes the temperature distribution uniform when the temperature rises, improves the heat treatment performance, and can heat treat even a large article.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention according to claim 1 is such that a heated gas passes through both sides of each of the divided stages. A flat plate-like article made of a rectangular LCD glass substrate placed at each stage of the heat treatment section having an inlet and an outlet, and the direction from one end side to the other end side of the article is from the inlet to the outlet. In the heat treatment apparatus for heating the article placed as described above with the gas for heat treatment, the flow dividing means is provided with a plurality of openings and a guide plate provided in the openings, and the deflecting plates are provided in each of the stages. The flow dividing means is arranged in parallel with the article on at least one side of the article in the direction from the inlet to the outlet, and one side is electrically connected to at least most of the inlet and the other side is electrically connected to the outlet. The entrance and the exit A first chamber for partitioning the space between the first chamber and the second chamber for introducing the gas, the inlet side being wide and the outlet side being narrow, and the second chamber for discharging the gas, the inlet side being A second chamber that is narrow and wide on the side of the outlet, and the article is placed in the second chamber so as to face the flow dividing means, and the opening And the guide plate from the first chamber to the
The gas separated through the opening enters the second chamber.
Wherein at least said one surface formed of such blows in a direction substantially perpendicular to the entire flow in the direction of the one side of the article Te
And the gas entering the second chamber is in front of the second chamber.
After flowing in the direction of one side, from the one end side of the article to the front
It is characterized in that it is formed so as to flow in the direction of the other end side .

In addition to the above, the invention of claim 2 is characterized in that the one side has heating means for reheating the gas passing through the opening.

According to a third aspect of the present invention, in addition to the features of the first aspect, a heat storage means having a heat capacity sufficiently larger than that of the article is provided on the opposite side of the one side. To do.

According to a fourth aspect of the present invention, in addition to the features of the first aspect, the flow dividing means is provided on both sides of the article.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a structural example of a heat treatment apparatus to which the present invention is applied. The heat treatment apparatus is provided with a heat treatment section 3 in a main body 2 which is surrounded by a heat insulating wall 1 and is hermetically sealed.
Hot air, which is a gas heated by the main heater 4, is circulated and supplied by the blower 5 to pass from the inlet 6 to the outlet 7 of the heat treatment unit 3,
It is a device for heating a work W such as an LCD glass substrate, which is a flat article placed in the direction from the entrance to the exit, with hot air and heat-treating the work, and in the direction from the entrance 6 to the exit 7 of the work W in this example. It has a deflecting plate 8 as a flow dividing unit disposed on the upper surface side which is one surface side.

In the hot air circulation path indicated by the arrow, the heat treatment section 3
A high-performance filter 9 for removing dust and an air passage 10 for guiding hot air thereto are provided on the upstream side of, and the hot air that has passed through the heat treatment section 3 is led again to the main heater 4 in the air passage 11. The heat treatment section 3 may have a single stage, but in this example, it is 6
It is divided into steps. Although not shown,
An opening for entering and exiting the work and a door for opening and closing the work are provided for each step on the front side of the front surface of the paper.
An operation control panel for operating and controlling various equipment is also provided at an appropriate position.

The deflecting plate 8 is electrically connected to the inlet 6 on one side and to the outlet 7 on the other side, and in this example, a plurality of openings 8a and guide plates 8b are provided so that the divided air flows in the direction toward the upper surface of the work W. Is equipped with. Due to the deflecting plate 8, each stage of the heat treatment unit 3 accommodates the first chamber 31 for introducing the hot air that has passed through the high-performance filter 9 and the work W and discharges the hot air.
It is divided into a chamber 32 and the first chamber 3 parallel to the work W.
The hot air that flowed into 1 was split into small sections and flowed in the direction of 9
The work W can be blown out at a substantially right angle over the entire upper surface of the work W deflected by 0 ° and accommodated in the second chamber 32. As will be described later, the deflecting plate 8 is intended to make the temperature distribution uniform when the workpiece is heated. Therefore, if the temperature rise on the upstream side is delayed, the inlet 6 is extended and a small amount of hot air is supplied to the second side. It may be introduced directly into the room.

The opening 8a has an appropriate shape such as a grid or honeycomb shape, and the opening ratio is, for example, about 50%. Such a shape and an opening ratio are determined so that the temperature of the work W can be efficiently increased with heat exchange efficiency and uniformly based on various conditions such as the amount of circulating air and the shape and size of the heat treatment section 3.
For example, if the volume of the first chamber 31 is sufficiently large, the hot air is blown out from the opening 8a due to the static pressure inside the chamber and becomes a blowing direction close to a right angle with respect to the deflecting plate 8, but on the other hand, the device becomes large. Become. Therefore, although the blowing direction of the hot air from the opening 8a is usually affected by the dynamic pressure,
In this case, the guide plate 8b acts to correct the blowing direction.

For efficient and uniform heating of the work,
It is desirable that the blowing angle of hot air be close to 90 °,
For example, the direction may be inclined from 90 ° to 45 °. Also in this case, turbulent flow is generated, which has the effect of considerably improving the heat exchange efficiency. In addition, for example, the flow velocity of the hot air decreases at the opening near the wall due to the frictional resistance of the wall, and the air volume accumulates as it progresses from the inlet to the outlet. Since the conditions and the effect of heating the work are different, if the aperture ratio of the deflection plate 8 is partially changed to change the amount of passing air and the distribution of the amount of heat supplied to the surface of the work is adjusted appropriately, further uniform heating can be achieved. Can be realized.

Further, the opening portion of the deflection plate 8 may be formed of a slidable plate so that the aperture ratio and the aperture shape can be changed. Also, the wind speed of the hot air passing through the opening 8a and the opening 8
The guide plate 8b may be omitted depending on the size of a or the like. On the contrary, it is possible to use a flow dividing method in which the guide plate 8b is made large and the aperture ratio is close to 100%. Further, depending on the degree of the turbulent flow effect and the like, it is possible to form not the openings like the grids but the openings communicating with each other in the length direction of the guide plate 8b.

In the present example, a work temperature raising heater 12 is further provided on the side of the first chamber 31, which is one side of the deflecting plate 8, as a heating means for reheating the hot air passing through the opening 8a. The heater 12 may be integrally formed as a whole, but is a split type in this example. If each of the divided heaters 12 for raising the temperature of the work is made to have a different capacity, the heating temperature can be partially changed to raise the temperature of the work W more uniformly.

Further, a heat storage plate 13 as a heat storage means having a heat capacity sufficiently larger than that of the work W is provided on the lower surface side of the work W opposite to the upper surface side. Work W
Although not shown, a plurality of pins are projected from the heat storage plate 13 to be supported at an appropriate height position. In addition, if it is necessary to shorten the temperature rising time of the heat storage plate 13 when starting the heat treatment apparatus,
A simple heater for raising the temperature may be built in the heat storage plate.

The heat treatment apparatus as described above is used as follows. The main heater 4 and the blower 5 are operated, and inside the main body 2, a predetermined temperature for heat treatment, for example, a temperature of 230
Hot air of about ° C is circulated. In this state, the work to be heat-treated is carried into the heat treatment section 3 by an appropriate work carry-in / carry-out device such as a robot provided outside the heat treatment apparatus. In conjunction with this, the work temperature raising heater 12 in the stage in which the work is put into operation is operated, and the hot air of a predetermined temperature flowing into the first chamber 31 is reheated a few degrees higher and passes through the deflection plate 8. And is sprayed on the top surface of the workpiece almost at right angles.

By such hot air heating, the temperature of each part of the work uniformly rises within a small temperature distribution difference range.
FIG. 2 is an estimation of the general tendency of factors that raise the temperature of the work in the temperature rising process. In the figure, the horizontal axis indicates the position in the direction from the work inlet to the work outlet (L direction),
(A) to (D) are the heat treatment apparatus of the present invention.
(D) is a conventional heat treatment apparatus.

The amount of heat qi transferred from the hot air to the work per unit time to raise the temperature of the work (i is the i-th work part corresponding to the i-th direction from the inlet 6 to the outlet 7 of the deflection plate 8) is generally , Qi = Ki Fi θi = C (ti-tj) gi (Kcal / h
r). Where K is the heat transfer coefficient (Kcal / m ² · hr · °
C), F is the heat transfer area (m ² ), θ is the temperature difference between the hot air and the work (° C), C is the specific heat of the hot air (Kcal / kg ・ ° C), t
Is the temperature of hot air and g is the flow rate of hot air (kg / hr). Figure 2
In the above, the amount of transferred heat, the factors that determine the amount of transferred heat, and the temperature distribution when the temperature rises are continuously shown in the length L direction of the work. Also, the state at the start of temperature rise is shown by a solid line, and the state at the time when the temperature rise is almost reached is shown by a chain line. The thick line shows the temperature distribution in the work when any part of the work reaches the heat treatment temperature.

FIG. 2 shows characteristics of factors related to the heat transfer ability. In the conventional device, the heat transfer coefficient K is high because the hot air flows in a parallel laminar flow with respect to the work, so that the flow is slightly disturbed near the inlet and becomes high, and it is almost constant and low in the L direction. In the present apparatus, the hot air flows toward the work surface, collides, and becomes a turbulent state to flow in the outlet direction, so that the value is high and increases in the L direction as the flow velocity increases.
In addition, since the flow rate is small near the inlet, K decreases,
It is possible to suppress the decrease by directly contacting the work with hot air and by relatively increasing the aperture ratio. In the conventional device, the temperature difference θ is equal to L
Although the amount of decrease in the direction is large near the inlet and gradually decreases thereafter, in the present apparatus, new hot air is sequentially replenished, so the degree of decrease is small. Both values are small in the vicinity of reaching the temperature rise of the chain line. However, since the apparatus for heating the workpiece is provided in the apparatus of this example, a certain temperature difference can be obtained even in the vicinity of the time when the temperature rise is reached.

From the above K and θ tendencies, the amount of heat transfer that can be supplied to the workpiece is large on the upstream side in the conventional apparatus and small on the downstream side at the start of temperature rise, while it is about the same in this apparatus. To do. As a result, the total amount of heat that can be supplied to the workpiece from the start of temperature increase to the time when temperature rise reaches is large on the upstream side in the conventional device and small on the downstream side, but is about the same in this device. The temperature distribution of the work that reflects this, as shown by the thick line, has a large difference between the upstream side and the downstream side in the conventional apparatus, but is uniform in this apparatus. The right side of the previous equation shows the heat radiation capacity of hot air,
Of course, the same result can be obtained with this formula.

As described above, the apparatus of the present invention can greatly improve the temperature distribution of the work as compared with the conventional apparatus. In this case, if only the hot air at the predetermined temperature is heated, the temperature difference between the work and the hot air becomes smaller as described above, the heat exchange amount decreases, and the temperature rise of the work becomes extremely slow, which is necessary for heat treatment. It takes a long time to reach the lower limit temperature, which is set to the lower limit temperature of the work by supplying hot air several degrees higher than the predetermined temperature by the work temperature raising heater 12 as in this example. The arrival time can be greatly shortened.

When it is predicted that the temperature of the work rises to reach the predetermined temperature as described above, the operation of the work temperature raising heater 12 is stopped, and thereafter, the hot air controlled to the predetermined temperature is heated. The temperature distribution of the work that remains slightly is settled, and uniform baking is performed.

When the heat treatment of the work on one stage is completed,
The work on that stage is unloaded and a new work is loaded. In this case, in the heat treatment apparatus in which the heat treatment section 3 is configured in multiple stages in the main body 2, since each stage is partitioned by the heat storage plate 13, the work of the particular stage does not disturb the temperature of the other stages. . Further, the heat storage plate 13 absorbs the thermal influence of the work piece temperature raising heater 12 in the lower stage on the work piece in the upper stage, and suppresses the turbulence in the room temperature when a new work is carried in. , Has the effect of radiating heat to the newly loaded low temperature work and assisting its temperature rise.

FIG. 3 shows an example of a heat treatment apparatus in which the deflection plates 8 are provided on both sides of the work W. In this example, the heat storage plate 13 of the example of FIG. 1 is not provided, but the lattice-shaped shelf 14 is provided, and like the case of the heat storage plate 13, the work W is supported from the shelf 14 by a plurality of pins (not shown). Has been done. Lattice shelf 1
4 has rough eyes and allows passage of hot air. As a result, the work W is heat-treated by supplying hot air to the front and back surfaces thereof at substantially right angles. A partition plate 15 separates the stages of the multi-stage heat treatment section 3 from each other to prevent mutual interference of the work temperature raising heaters 12 of the stages.

As the start / stop control of the heater 12 for raising the temperature of the work, as in the example of FIG. 1, time control until the temperature is raised in association with the introduction of the work can be used, but in this example,
A temperature sensor 16 is provided on the downstream side of the hot air in the second chamber 32 to detect the hot air temperature at the downstream portion, and when the hot air temperature reaches a predetermined low temperature due to the heat absorption of the low-temperature work carried in, the work temperature raising heater 12 is activated. When the temperature of the work rises and the temperature drop of the hot air decreases and the detected temperature returns to a predetermined high temperature, the heater 12 is controlled to stop. However, heater 1
As the temperature control of 2, the control method described in FIG. 1 can be used. It is also possible to use the temperature control of the example of FIG. 3 for the apparatus of the example of FIG. It is needless to say that the heat treatment apparatus of this example also has the effect of making the temperature distribution uniform when the workpiece is heated.

[0030]

As described above, according to the present invention, in the invention of claim 1, the flow dividing means is provided at least on one side of the flat article in the direction from the inlet through which the heated gas passes to the outlet. Since the flow dividing means is provided, the flow dividing means is arranged, for example, in parallel with one side of the flat article. Since one side of the flow dividing means is electrically connected to at least most of the gas inlet and the other side thereof is electrically connected to the gas outlet, the flow dividing means forms a partition between the inlet and the outlet. Then, since the plurality of openings are provided so that the air separated in the direction of the one side of the article flows, the gas enters the heat treatment section from the inlet, is separated and flows through the opening in the direction of the article, Then you will reach the exit.

Due to such a gas flow, the gas that has already been split and flows on the article side and the newly split gas collide and mix with each other in the direction from the inlet side to the outlet side of the article. A turbulent state occurs, the heat transfer coefficient with the article increases, and the gas that has been heated and has not decreased in temperature is always additionally supplied by a new shunt, so the gas temperature after transferring heat to the article Is reduced.

As a result, the heat transfer coefficient increases from the upstream position to the downstream position of the gas in the article, the decrease in the temperature of the gas due to heat exchange with the article decreases, and the temperature difference between the gas and the article accompanying this decreases. Phenomena such as suppression of decrease, replenishment of new amount of heat, etc. act favorably, the heat transfer amount from the gas to each part of the article becomes uniform, and the temperature distribution difference in the article when the article reaches the heat treatment temperature is reduced. It can be made small enough. Therefore, the heat treatment quality of the article can be improved. Further, in such a heat treatment apparatus, there is no need to significantly increase the air volume or pressure of the blower that circulates the gas, and it is not necessary to upsize the high-performance filter that is usually provided, so that the component equipment of the apparatus is large. There is no increase or cost increase.

According to the second aspect of the present invention, since the heating means for reheating the gas passing through the opening is provided on one side of the flow dividing means that is in communication with the inlet, the article at room temperature is put in the heat treatment section and the heat treatment temperature is reached. By operating the heating means when the heat absorption of the article is large, and by reheating the heated gas introduced into the heat treatment section to raise the temperature to the heat treatment temperature or higher,
It can assist the rapid temperature rise of the article. As a result, the heat treatment efficiency can be increased. Further, it is possible to suppress the ability of an ordinary heater, which is determined in consideration of the amount of heat when the article is heated.

In the third aspect of the present invention, since the heat storage means having a heat capacity sufficiently larger than that of the article is provided, it is possible to suppress temperature disturbance in the heat treatment section when the article is newly carried into the heat treatment section, and thereafter A uniform temperature rise of the article can be assisted. As a result, the temperature distribution of the article when the heat treatment temperature is reached can be further improved. Further, even if the temperature of the heated and circulated gas fluctuates, the article temperature can be stabilized and the heat treatment quality can be improved.

In the invention of claim 4, since the flow dividing means is provided on both sides of the article, the article can be heated more quickly and the heat treatment efficiency can be improved. Further, the flow velocity of the gas on the surface of the article can be reduced to reduce the influence of the gas flow on the circuit and the like formed on the surface.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a heat treatment apparatus to which the present invention is applied.

2 (A) to (D) and (a) to (d) are curve diagrams showing the general tendency of the action and effect of the heat treatment apparatus and the conventional heat treatment apparatus, respectively.

FIG. 3 is an explanatory diagram showing another example of the heat treatment apparatus to which the present invention is applied.

[Explanation of symbols]

3 heat treatment department 6 entrance 7 exit 8 Deflecting plate 8a opening 12 Heater for heating work (heating means) 13 Heat storage plate (heat storage means) W work (flat article)

Continuation of front page (56) Reference JP-A-9-28565 (JP, A) JP-A-6-317514 (JP, A) JP-A-62-172539 (JP, A) JP-A-61-105843 (JP , A) Actual development Sho 60-156399 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) F27B 17/00

Claims (4)

(57) [Claims] 1. A rectangular LCD glass substrate placed in each stage of a heat treatment unit having an inlet and an outlet through which heated gas passes on both sides of each of the stages formed by dividing into a plurality of stages. In a heat treatment apparatus for heating the article by the gas, the flat article being formed so that the direction from one end side to the other end side of the article is from the inlet to the outlet, The flow dividing means comprises a deflecting plate provided in each of the stages, the flow dividing means having an opening and a guide plate provided in the opening, and the flow dividing means includes at least one surface of the article in a direction from the inlet to the outlet. A first chamber that is arranged in parallel with the article on one side and has one side that communicates with at least most of the inlet and the other side that communicates with the outlet and partitions the inlet and the outlet to introduce the gas. The entrance side is wide Wide side of the second chamber is a by the inlet side is narrow the outlet of the first chamber and the gas side of the outlet is narrower is discharged
Is in the second chamber has been arranged to form, the article is not placed in the second chamber so as to face the diverter means, and said opening and said guide plate, said first From the chamber to the opening
The gas separated by passing through is formed to flow in a direction of at least the one side the one side is blown in a direction substantially perpendicular to the entire area of the front <br/> Symbol article contained in said second chamber to
In the second chamber, the gas that has entered the second chamber is on the one surface side.
After flowing in the direction from the one end side of the article to the other end side
A heat treatment apparatus , which is formed so as to flow in a direction . 2. The heating means for reheating the gas passing through the opening is provided on the one side.
The heat treatment apparatus according to. 3. The heat treatment apparatus according to claim 1, further comprising a heat storage unit having a heat capacity sufficiently larger than that of the article, on the side opposite to the one side of the article. 4. The heat treatment apparatus according to claim 1, wherein the flow dividing means is provided on both sides of the article.