JP2001358206A - Method and apparatus for cooling board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly cool and convey a glass board having a large size and being a thick plate to be cooled in non-contact in a short time. SOLUTION: A table of a flat plate equivalent to four sides of the glass board having the large size and being the thick plate is horizontally disposed. A plurality of jet ports each for injecting air flows in a vertical direction and an oblique direction are provided at everywhere on the table. The board is conveyed from a previous step in a state in which the cooling air flows are injected from the plurality of the ports, the board is levitated in a non-contact state, and the board is fluctuated at some times to uniformly air current cools the board in a short time, and sent to a next step when becoming a set temperature or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing a large and thick glass substrate typified by a plasma display panel (hereinafter abbreviated as "PDP"). The present invention relates to a method and apparatus for uniformly and cleanly cooling the entire surface in a non-contact state.

[0002]

2. Description of the Related Art For example, in a process of vertically extending a rib of a large and thick PDP glass substrate (diagonal length: 1.8 m, thickness: 3 mm), printing, heating and drying are repeated more than ten times. . At that time, in order to maintain the printing accuracy, it is necessary to maintain the substrate temperature at the time of printing within 25 ± 2 ° C. On the contrary, the temperature at the time of drying immediately after printing is also heated to 150 ° C. . It is required that these dozens of temperature cycles be performed in a short time and uniformly from both aspects of quality and productivity.

In response to this requirement, Japanese Patent Application Laid-Open No. H11-43337 entitled "Glass Substrate Cooling Apparatus" discloses that a plurality of cooling panels are arranged at regular intervals at the same level to form a wide cooling zone. In addition, by disposing an intake nozzle and a vertically movable transport roller between the cooling panel gaps, the glass substrate is sucked, brought into contact with the cooling panel, cooled, and is not cooled in the gap area between the cooling panel arrangements. After raising the glass substrate vertically in the area of the glass substrate that has been moved vertically and horizontally, it is placed on the next cooling panel and a method and apparatus for cooling uniformly in a short time has been disclosed. The objective of performing the temperature cycle in a short time and uniformly in terms of both quality and productivity has been sufficiently achieved and widely used.

[0004]

However, in the above-mentioned method, since the substrate to be cooled is not cooled in the gap between the adjacent cooling panels, a single cooling step is required.
The phase is shifted by lifting and horizontally moving the substrate a plurality of times, and then cooled by repeating descending and contacting the cooling panel. Therefore, as a loss in the step of shifting the phase, about 10 seconds in addition to the cooling time are required. Needed some extra time.

Further, in the case of a glass material, unlike a metal, the thermal conductivity is low, so that during the first cooling, the cooled area and the uncooled area of the entire substrate surface alternately have a stripe pattern of temperature distribution. To form In particular, when the direction of the printed rib is more parallel than when it is orthogonal to the transport direction, the amount of heat shrinkage varies intermittently in the length direction of the rib, and the stress and strain applied to the rib Has become uneven and an undesirable phenomenon has occurred.

In addition, the above-mentioned cooling method and apparatus require three utilities of cooling water, a vacuum pump for sucking the substrate, and drive control as utilities, so that piping and wiring are complicated, and the cost of the apparatus is increased. Was. In particular, the use of cooling water is not preferable because it causes dew condensation on the pipe surface in the clean room.

On the other hand, as a method of air cooling, a method of hitting cool air from around or above a glass substrate has been known. However, this is a method in which the substrate is placed on a support, and air is blown on the lower surface of the substrate. The cooling efficiency is poor for the air volume
The temperature distribution around and above the glass substrate was not uniform, and it took a long time to cool. Therefore, it is hardly adopted.

[0008]

According to the present invention, a substrate heated to a high temperature in an upstream process (for example, in a drying furnace) is transferred to an airflow floating / cooling table having a plurality of air injection ports. After being mounted and suspended in a state of floating for a predetermined time, the cooling to a predetermined temperature is confirmed by a temperature monitoring camera, and then sent out to the next process (for example, PDP rib printing). At this time, in order to prevent the accident of overlapping of the substrates in each process, a substrate presence / absence detection sensor is provided in each process and a stopper is provided between the processes, and before the next process is sent, the substrate presence / absence detection sensor must be used for the next process. After confirming that there is no substrate,
The substrate is sent out with the stopper opened.

Here, the airflow floating / cooling table having an air injection port is larger in size than the substrate and has a sufficient number of injection ports, and the outlet of the cooling air coming out of the injection port is located at the periphery of the substrate. Since the cooling air is only on the sides, the cooling air is released on the four sides after licking the lower surface of the substrate, so that the substrate can be uniformly cooled over the entire surface of the substrate by simply floating the substrate on the airflow and cooling table. It becomes possible. By compressing the gas to be sent and releasing the pressure at the stage of sending, a considerable cooling effect can be obtained, or if necessary, to cool the air positively, cool the gas sent to the flow path to the air flow levitation and cooling table if necessary A heat exchanger can also be provided.

Further, in addition to the upper vertical injection port for air flow floating and cooling on the cooling table, an upwardly inclined injection port for appropriately moving the substrate forward and backward or swinging left and right is disposed at an appropriate time so that the substrate can be air-flowed. By swinging on the floating / cooling table plate, the relative position between the lower surface of the substrate and the injection port was shifted, so that the uniform cooling and the cooling time could be further reduced.

Further, when the substrate is moved forward and backward, and is swung right and left, the airflow floating and cooling table is tilted and swung obliquely back and forth and right and left by using a cylinder, a link mechanism or a cam mechanism, so that the weight of the substrate is reduced. As a result, as in the case where the substrate was oscillated and the inclined injection port was provided, uniform cooling and a reduction in cooling time could be obtained.

The apparatus and the cooling method are applicable to a glass substrate used for a liquid crystal display panel in which the trend toward larger screens is progressing, an amorphous silicon vapor-deposited substrate for a solar cell, a polymer film substrate, a metal film / polymer film laminate. The present invention is also applied to a cooling process of a heating plate such as a material, a painted or washed metal sheet.

[0013]

Next, embodiments of the present invention will be described with reference to examples.

[0014]

(Embodiment 1) FIG. 1 is a plan view including a process before and after a case of cooling a substrate (in some cases, residual heat of a substrate) using an airflow floating and cooling table according to the present invention.
FIG. 2 is a sectional view taken along line AA in FIG. The configuration includes a standby loading step (hereinafter, referred to as “station I”), a substrate cooling step (hereinafter, “station II”), and a substrate unloading section (hereinafter, “station III”). Station I and Station III
Then, the transport roll shaft 2 is driven by a power transmission mechanism such as a power motor or a chain or a belt (not shown) at the lower surface level of the substrate to be transported, and the rollers 3 that rotate intermittently at the same level therethrough. Are arranged. A pair of guard rails 6 are attached to both ends of the roller 3 to prevent the board from falling. Each station I,
Between II and III, stoppers 4 and 5 which can move up and down in order to prevent the succeeding substrate 1 from colliding with the stopped preceding substrate 1 are arranged. The stoppers 4 and 5 are a substrate presence / absence detection sensor 1 installed on the upper surface of the substrate.
It moves up and down in response to the command of 6. At the same time, the stopper 5 is connected to the temperature monitoring camera 1 in the station II.
7 to move up and down in response to a command based on the temperature of the substrate 1 measured by the controller 7.

The structure of the station II is the same as or lower than the level of the horizontal line on the lower surface of the substrate 1 when the airflow floating and cooling table 8 connected to the compressor 7 through the pipe supports the substrate 1 on the upper surface of the roller 3. is set up.
(Note: If the height is equal to or higher than that, it will be an obstacle to loading from the station I.) On the upper surface of the airflow floating and cooling table 8, a vertical outlet 9 having a predetermined diameter is provided at a predetermined pitch vertically upward. I have. The air discharge may be continuous,
It is economically preferable to start the ejection immediately before the substrate 1 enters the station II and stop the ejection immediately after the substrate 1 is carried out to the station III.

At the stage of sending the gas from the compressor 7 to the airflow floating / cooling table 8, a considerable cooling effect can be obtained by releasing the pressure. However, as a method of actively cooling, the airflow floating from the compressor 7 is performed. A heat exchanger 18 can also be provided to send the cooled gas to the pipe between the cooling tables 8.

A temperature monitoring camera 17 of, for example, an infrared sensing type provided immediately above the substrate 1 being cooled detects that the substrate temperature has reached a predetermined temperature range and a predetermined uniformity, and indicates that the stopper 5 has dropped. No, but it is sent out to the next station III by the unloading pusher.

In the first embodiment, the substrate 1 is located at an arbitrary position in the area of the station II.
The amount of the injection air and the injection port are sufficiently large, and the injected air is a gap between the upper surface of the airflow floating and cooling table 8 of the station II and the lower surface of the substrate 1 (typically about 0.2 to 0.5 mm).
Is licked over the entire surface of the lower surface of the glass and is released from the four sides of the substrate 1, so that the cooling efficiency is high and the temperature distribution in the cooling process becomes uniform. That is, the portion (near the area) immediately above the ejection port of the substrate 1 does not become a cold spot (cold spot). (Embodiment 2) FIG. 3 shows a case where all the air injection ports provided on the surface of the airflow floating and cooling table 8 of the station II are vertical injection ports 9 in the vertical direction. FIG. 4 is an enlarged cross-sectional view of a table 8 portion, showing an example in which a relative relationship between a position of an air injection port with respect to a lower surface of the substrate 1 is not intentionally moved. (Embodiment 3) FIG. 4 shows an embodiment of an airflow floating / cooling table provided with a substrate swinging mechanism by an oblique airflow injection method. A vertical injection port 9 is provided at the center of the surface of the airflow floating and cooling table 8 at the station II, and an oblique injection port 10 which is inclined toward the center of the airflow floating and cooling table 8 at the peripheral portion.
In order to independently control the injection and stop of the air injection from the vertical injection port 9 and the oblique injection port 10, the partition plate 11,
12 is provided to divide the hollow body portion of the airflow floating / cooling table 8 into three chambers A, B, and C. Although not described, air to the chambers A, B, and C can be independently distributed. It is configured to be possible, and the air sending switching valve is also independent. FIG.
In the case of a solid arrow with respect to the flow of air from the middle and vertical injection ports 9 and the oblique injection ports 10, that is, in a state where the substrate is floated and cooled by air injection from the vertical injection port 9 of the chamber B,
By performing injection from the oblique injection port 10 only in the chamber A,
The substrate 1 is moved rightward, and subsequently, the ejection from the oblique ejection port 10 of the chamber A is stopped, and the ejection is performed from the oblique ejection port 10 of the chamber C, whereby the substrate 1 is moved leftward. By repeating this, the substrate 1 can be swung on the airflow floating and cooling table 8. Therefore, in the case of cooling the substrate 1, the relative position of the lower surface of the substrate 1 is shifted by swinging to the vicinity of the cooling outlet having the lowest temperature.
More uniform substrate cooling was enabled than the methods described in (Example 1) and (Example 2). (Embodiment 4) This embodiment is another embodiment for achieving uniform cooling of a substrate. FIG. 5 shows an embodiment of an airflow levitation and cooling table provided with a substrate swinging mechanism by an inclined sliding method by the substrate's own weight. Is shown. The principle that the substrate 1 floating on the airflow floating and cooling table 8 easily moves by its own weight due to a slight inclination is applied. For example, a mechanism using a hinge 13 whose one end can be turned and a lifting mechanism 15 using the hinge 14 and a pneumatic or hydraulic cylinder, link or cam mechanism at the other end.
Is moved up and down by a very small amount to swing the upper surface of the airflow floating and cooling table 8 back and forth, and in some cases, left and right to shift the relative position between the vertical injection port 9 and the lower surface of the substrate 1.

[0019]

According to the prior art, in the method and apparatus for cooling a substrate, water for cooling, a vacuum pump for sucking the substrate, and drive control are required as utilities, so that piping and wiring become complicated. The equipment cost was high. In particular, the use of cooling water is not preferable because it causes dew condensation on the pipe surface in the clean room. However, in the present invention, since no cooling water is used, the manufacture and assembly of the apparatus are simplified, and measures against dew condensation on the surface of the cooling pipe are eliminated.

In the conventional method, cooling is not performed in the gap between the cooling panels provided with the substrates to be cooled.
For a single cooling step, the substrate is lifted and moved horizontally for a plurality of times to shift the phase, and then cooled by repeating descending and contacting the cooling panel, resulting in a loss time of about 10 seconds. Was. Further, in the case of a glass material, unlike a metal, the thermal conductivity is low, so that during the first cooling, a cooled area and an uncooled area of the entire glass substrate surface alternately form a stripe pattern of a temperature distribution. I do. In particular, when the direction of the printed rib is more parallel than when it is orthogonal to the transport direction, the amount of heat shrinkage varies intermittently in the length direction of the rib, and the stress and strain applied to the rib Has become uneven and an undesirable phenomenon has occurred. On the other hand, in the method according to the present invention in which the cooling air uniformly contacts the entire lower surface of the substrate, the entire surface can be uniformly cooled, the substrate does not need to be intermittently moved, and there is no loss time, and cooling that leads to a predetermined temperature. The time was greatly reduced.

In the present invention, since uniform cooling is possible,
When an object having a different coefficient of linear expansion or a different shape provided on a substrate (for example, a PDP substrate has a laminated printed rib, etc.), residual stress, distortion, peeling from the substrate, and the inside of the rib may occur. The occurrence of defects such as fine cracks is drastically reduced. Accordingly, the dependency between the rib forming direction and the transport direction is eliminated, and the production control is facilitated, and the necessity of providing a 90-degree turning table of the substrate as a measure for avoiding the above-mentioned defect is eliminated.

The compressed air injected from the upper surface via the air outlet through the hollow body of the airflow floating / cooling table has the effect of lowering the temperature at the time of injection due to the adiabatic expansion effect of air.
The cooling effect of the substrate is further enhanced. In parallel, FIG.
As shown in FIG. 5, by providing a substrate swinging mechanism on the airflow cooling table, the relative position between each injection port for cooling and the lower surface of the substrate is shifted, so that cooling can be made more uniform and shorter. I was able to measure.

[Brief description of the drawings]

FIG. 1 is a plan view including a process before and after a case of performing substrate cooling (in some cases, substrate residual heat) using an airflow floating and cooling table according to the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 3 is a detailed view of an airflow floating and cooling table in FIG. 1;

FIG. 4 is an embodiment of an airflow floating and cooling table provided with a substrate swinging mechanism by an oblique airflow injection method.

FIG. 5 is an embodiment of an airflow levitation and cooling table provided with a substrate swinging mechanism by an inclined sliding method by a substrate's own weight.

[Explanation of symbols]

 1: Substrate 2: Transport roll shaft 3: Roller 4: Stopper 5: Stopper 6: Guard rail 7: Compressor 8: Air flow floating and cooling table 9: Vertical jet port 10: Oblique jet port 11: Partition plate 12: Partition plate 13 : Hinge 14: Hinge 15: Lifting mechanism 16: Board presence detection sensor 17: Temperature monitoring camera 18: Heat exchanger

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Atsushi Hashimoto 1-45-1, Oe, Otsu City, Shiga Prefecture Toray Engineering Co., Ltd. F-term (reference) 5F031 CA05 FA02 FA07 GA53 GA63 HA38 HA39 HA56 JA01 JA04 JA22 JA46 MA30 PA18

Claims (8)

[Claims] 1. A flat substrate to be cooled is placed on a table top surface of a hollow body having a plurality of gas injection ports provided at a predetermined diameter and a predetermined pitch on a horizontal attitude plane having an area larger than the substrate area. A method of cooling a substrate, wherein the substrate is floated by air flow and cooled by air flow. 2. The method for cooling a substrate according to claim 1, wherein the substrate is transferred to a next step after the temperature of the substrate on the airflow floating / cooling table reaches a set temperature or lower. 3. After confirming that there is no substrate in the next step,
3. The method for cooling a substrate according to claim 1, wherein the substrate on the airflow floating and cooling table is transferred to a next step. 4. An arrangement of gas injection ports for the airflow floating and cooling table, wherein at least a region corresponding to the front and rear peripheral portions in the substrate transport direction is provided with an injection port inclined toward the airflow floating and cooling table center. 4. The method of cooling a substrate according to claim 1, wherein a vertical injection port is provided in an upper part, and the direction of the airflow injection is changed to swing the substrate by controlling the injection. 5. The substrate according to claim 1, wherein the substrate is swung by its own weight and a levitation force by inclining the entire airflow floating / cooling table at least back and forth in the transport direction of the substrate. Substrate cooling method. 6. A cooling device for a substrate, comprising: a table of a hollow body having a plurality of gas injection ports arranged at a predetermined diameter and a predetermined pitch on a horizontal attitude plane having an area larger than the substrate area. apparatus 7. An array of gas injection ports on a table for airflow floating and cooling, which is provided at least in an area corresponding to the front and rear peripheral portions in the substrate transport direction, with injection ports inclined toward the center of the table for airflow floating and cooling. 7. The cooling device for a substrate according to claim 6, wherein a vertical opening directed upward is provided at a central portion of the substrate. 8. The apparatus for cooling a substrate according to claim 6, wherein a mechanism is provided for inclining the entire table for floating and cooling the airflow at least in the forward and backward directions in the direction of transport of the substrate.