JP2008256229A - Firing furnace and firing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a firing furnace and a firing method capable of uniformly cooling a glass substrate in a short time without deforming and cracking the glass substrate. <P>SOLUTION: In this firing furnace for firing the glass substrate 10 by allowing the glass substrate 10 loaded on a setter 11 to pass through a heating chamber 5 and a cooling chamber 7 while being conveyed, the cooling chamber 7 is provided with a cooling means and a measuring means for measuring a condition of the glass substrate 10, and the cooling means is controlled on the basis of a result of the measurement by the measuring means. As cooling by the cooling means can be performed according the condition of the glass substrate 10, firing can be performed while suppressing deforming and cracking. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a baking furnace and a baking method for baking a glass substrate such as a plasma display panel.

  In recent years, practical use of a large-screen flat panel that can be used as a wall-mounted television or a multimedia display has been steadily progressing. As such a large-screen flat panel, a plasma that combines the advantages of self-luminous, wide viewing angle, good display quality, and the manufacturing advantage of simple manufacturing process and large size. A display panel (hereinafter referred to as “PDP”) is cited as one of the most promising candidates.

  The PDP is manufactured by applying various materials to be baked, such as electrodes, dielectrics, and barrier ribs on the surface of a large glass substrate called a front glass and a back glass, drying, and firing, and finally forming the final glass. For example, the front glass and the rear glass are sealed.

The firing of the glass substrate is performed using a firing furnace in which the glass substrate is fired by passing the heating unit and the cooling unit while conveying the glass substrate mounted on the setter. In response to demands for further increase in size of PDP, productivity improvement by multi-chamfering, and reduction of tact time, large glass substrates are required to be heated and cooled quickly without causing warping or cracking. It has been. In particular, since the glass substrate placed on the setter has a large heat capacity, the cooling of the lower surface of the glass substrate in contact with the setter is slower than the cooling of the upper surface of the glass substrate. Due to the temperature difference between the upper surface and the lower surface, the glass substrate has a shape in which the end warps upward with respect to the central portion. In order to prevent this, a method of cooling while suppressing warping by blowing cooling air to the lower surface central portion of the setter on which the glass substrate is placed and the vicinity thereof has been proposed (for example, Patent Documents). 1).
JP 2003-331724 A

  However, when the size of the glass substrate and the firing conditions are different, the manner of warping and distortion differs. Therefore, the cooling air blowing condition for preventing the projection from being lowered differs depending on the state of the glass substrate. Moreover, since it is difficult to uniformly cool the edge of the glass substrate only by blowing the cooling air to the center, there is a problem that the glass substrate remains strained or cracks occur.

  The present invention has been made in view of these problems, and provides a firing furnace and a firing method that can be uniformly cooled in a short time without causing distortion or cracking of the glass substrate. Objective.

  The firing furnace of the present invention is a firing furnace having a heating part and a cooling part therein, and firing the glass substrate by passing the heating part and the cooling part while conveying the glass substrate mounted on the setter, The cooling unit includes a cooling unit and a measuring unit that measures the state of the glass substrate, and is configured to control the cooling unit based on a measurement result of the measuring unit.

  According to such a structure, since it can cool with the cooling means according to the state of the glass substrate, the baking which suppressed distortion and a crack can be performed.

  Furthermore, it is desirable that the cooling means is a cooling place changing means for changing the cooling place on the glass substrate, and cooling that can more reliably suppress distortion and cracking can be performed.

  Furthermore, it is desirable that the measuring means is a warpage amount measuring means for measuring the warpage amount of the glass substrate, and by performing cooling that appropriately reduces the warpage amount, distortion and cracking of the glass substrate can be suppressed. .

  Furthermore, it is desirable that the measuring means is a glass substrate or a surface temperature measuring means for measuring at least one surface temperature of the setter, and cooling can be performed so as to reduce distortion due to the difference in surface temperature.

  Further, it is desirable that the cooling unit includes a plurality of cooling chambers, and the glass substrate is transported between the cooling chambers. According to such a firing furnace, it becomes possible to perform cooling without being affected by an adjacent cooling chamber, and by performing cooling under precise control, distortion and cracking of the glass substrate can be suppressed. .

  Furthermore, it is desirable to change the cooling position on the glass substrate by the cooling means in the cooling chamber located downstream in the conveyance direction based on the measurement by the measurement means of the cooling chamber located upstream in the conveyance direction. It becomes possible to perform cooling suitable for the state, and cooling by precise control can be performed.

  Further, the firing method of the present invention is a firing method in which the glass substrate is fired by passing the heating unit and the cooling unit while conveying the glass substrate mounted on the setter, and the cooling unit is configured to change the state of the glass substrate. A measurement step for measuring and a cooling control step for controlling the cooling means provided in the cooling unit based on the measurement result of the measurement step are provided.

  According to such a method, since it can cool with the cooling means according to the cooling state of the glass substrate, distortion and a crack of a glass substrate can be suppressed.

  Furthermore, it is desirable to change the cooling location on the glass substrate in the cooling control step, which enables faster and more precise cooling.

  Furthermore, it is desirable to measure the amount of warpage of the glass substrate in the measurement step, and cooling can be performed to reduce the amount of warpage.

  Furthermore, it is desirable to measure at least one surface temperature of the glass substrate or setter in the measurement step, and cooling can be performed so as to reduce distortion due to the difference in surface temperature.

  Furthermore, it is desirable that the cooling unit includes a plurality of cooling chambers, and the glass substrate is desirably transported between the cooling chambers, so that the cooling can be performed without being affected by the adjacent cooling chambers.

  Furthermore, it is desirable that the cooling control step is performed in the cooling chamber located downstream in the transport direction based on the result of the measurement step in the cooling chamber located upstream in the transport direction, and cooling suitable for the cooling state of the glass substrate is performed. Therefore, it is possible to perform cooling by precise control.

  According to the present invention, it is possible to suppress warping or cracking of the PDP substrate and perform baking with high uniformity in a short time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing the structure of a firing furnace 1 according to the first embodiment of the present invention. The firing furnace 1 in the present embodiment includes an upper passage 2, a lower passage 3, a loader 4, a heating chamber 5 that constitutes a heating unit, a lifter chamber 6, a cooling chamber 7 that constitutes a cooling unit, an unloader 8, and a control device 9. Consists of.

  The glass substrate 10 is placed on the setter 11 by the loader 4 and is carried into the upper passage 2 from the inlet 12. The upper passage 2 is provided with a plurality of heating chambers 5 partitioned in the transport direction, and each heating chamber 5 includes a heater 13 for heating the glass substrate 10 and a glass substrate 10 together with a setter 11. A roller 14 for conveying is provided. The glass substrate 10 is heated by the heater 13 while being conveyed in the heating chamber 5 by the tact conveyance or continuous conveyance by the roller 14 and is baked. Although not shown, supply of air or the like required for firing, or exhaust gas generated by firing is performed as necessary.

  The glass substrate 10 fired in the upper passage 2 in this way is placed on the lifter 15 in the lifter chamber 6 on the opposite side to the inlet 12 and moves to the lower passage 3. The lower passage 3 has a plurality of cooling chambers 7 partitioned in the transport direction, and each cooling chamber 7 has an air supply port 16 and an exhaust port 17 that constitute a cooling means, a roller 14, and a measuring means. The sensor 18 is provided.

  The plurality of cooling chambers 7 are partitioned by a shutter 19. The glass substrate 10 moved to the lower passage 3 is tact-conveyed by the roller 14 in the cooling chamber 7 in the direction opposite to the conveyance direction at the time of firing in the upper passage 2. The shutter 19 opens and closes up and down and opens only when the glass substrate 10 is carried into the cooling chamber 7 by the roller 14 or carried out of the cooling chamber 7. In each cooling chamber 7, the glass substrate 10 is supplied with air from the upper air supply port 16a and the lower air supply port 16b, and is cooled by the cooling air exhausted from the upper exhaust port 17a and the lower exhaust port 17b. The

  The glass substrate 10 thus cooled is taken out of the setter 11 by the unloader 8 in front of the outlet 20 provided at the same furnace end as the inlet 12. The sensor 18 is disposed on the ceiling of the cooling chamber 7, measures the strain state of the glass, and transmits the measured value to the control device 9. The control device 9 controls the amount of cooling air supplied from the air supply port 16 and exhausted from the exhaust port 17 based on the measured value.

  Next, a control method by the control device 9 will be described in detail with reference to FIG. FIG. 2 is a cross-sectional view showing a firing step in the firing method according to the first embodiment of the present invention, and shows the lifter chamber 6 in the firing furnace 1 and the three cooling chambers 7 adjacent to the lifter chamber 6. It is sectional drawing. Hereinafter, the cooling chamber 7 adjacent to the lifter chamber 6 is sequentially referred to as a first cooling chamber 7a, a second cooling chamber 7b, and a third cooling chamber 7c.

  FIG. 2A shows a step of transporting the glass substrate 10 from the lifter chamber 6 to the first cooling chamber 7a. The glass substrate 10 descending from the upper passage 2 to the lower stage by the lifter 15 is carried into the first cooling chamber 7a by the roller 14 when the shutter 19 is opened.

  FIG. 2B shows a cooling step of the glass substrate 10 in the first cooling chamber 7a. In the first cooling chamber 7a, the glass substrate 10 is cooled by the cooling air supplied from the upper air supply port 16a and the lower air supply port 16b. After a predetermined time, the cooling step is ended by stopping the cooling air. . The cooling air in the cooling step is exhausted from the upper exhaust port 17a and the lower exhaust port 17b.

  FIG. 2C shows the measurement step. After completion of the cooling step, the sensor 18 measures the substrate shape.

  Note that FIG. 2 shows only one sensor 18 so as not to complicate the drawing. However, the central portion and the end portion of the glass substrate 10 can be measured so that the central portion and the end portion of the glass substrate 10 can be measured. A plurality of devices may be installed on the upper portion or the like, or a device that can measure a plurality of locations with a single sensor 18 may be used. These sensors 18 measure the height of the glass surface at a plurality of locations on the glass substrate 10 with laser light, and these measured values are sent to the control device 9. Based on these measurement values, the control device 9 detects which end of the glass substrate 10 is warped upward with respect to the central portion or warped downward.

  Note that the measurement step is not necessarily performed after the cooling step is completed, and may be performed in the middle of the cooling step.

  When the cooling step and the measurement step are completed, the transfer step is performed again, and the glass substrate 10 is transferred from the first cooling chamber 7a to the second cooling chamber 7b.

  FIG. 2D shows a cooling control step in the second cooling chamber 7b. The cooling control step in the second cooling chamber 7b is different from the cooling step in the first cooling chamber 7a in that cooling based on the control of the control device 9 is performed. First, the amount of cooling air supplied from the upper air supply port 16a and the lower air supply port 16b is determined according to the shape of the glass substrate 10 detected by the control device 9. For example, when the end of the glass substrate 10 is warped upward, the cooling air from the lower air supply port 16b is increased or the cooling air is decreased from the upper air supply port 16a in order to reduce the warpage. Is called. Accordingly, the exhaust amount from the upper exhaust port 17a and the lower exhaust port 17b is also changed as appropriate. The amount of air supplied from the air supply port 16 is controlled by, for example, the rotational speed of a fan (not shown) for supplying cooling air, the opening of a damper (not shown), or the like. Further, the amount of exhaust from the exhaust port 17 is controlled by, for example, the opening degree of a damper (not shown) of the exhaust port 17. Moreover, when the edge part of the glass substrate 10 has curved down, reverse control is performed.

  After the cooling control step is completed or during the cooling control step, the measurement step is performed again in the second cooling chamber 7b. In the subsequent transport step, the glass substrate 10 is transported in the third cooling chamber 7c, and the cooling control step is similarly performed in the third cooling chamber 7c based on the measurement result in the second cooling chamber 7b. By repeating such a measurement step and a cooling control step after the third cooling chamber 7c, it is possible to cool the glass substrate 10 while reducing warpage according to the state of the glass substrate 10. Therefore, the glass substrate 10 can be fired while suppressing distortion and cracking.

  Here, the above description has been made in an example in which only one glass substrate 10 is sequentially transported and cooled. However, in the actual implementation, the step of transporting the glass substrate 10 to the first cooling chamber 7a. When the process is completed, another glass substrate 10 baked through the upper passage 2 is transported by the lifter 15, and the glass substrate 10 is sequentially cooled. In this case as well, cooling can be performed according to the above.

  In addition, although the example which measures the height of the surface of glass with the sensor 18, detects the curvature state of the glass substrate 10 using the result, and performs cooling control was shown, if it is a method which can understand the distortion state of glass, For example, a temperature sensor may be used as the sensor 18 to detect the distortion of the glass substrate based on the distribution of the surface temperature of the glass substrate 10 and control the cooling. Further, the temperature distribution of the setter 11 may be measured, and the distortion of the glass substrate may be detected from the result.

  In the present embodiment, the description has been given of the firing furnace 1 having the upper passage 2 and the lower passage 3. Since such a firing furnace 1 can effectively use the installation area, it is desirable for firing a large glass substrate 10, but it is not essential to have the upper passage 2 and the lower passage 3. Can also be applied.

  Moreover, although the air supply opening 16 for cooling was installed in the upper side and the lower side of the glass substrate 10, the example at the time of cooling the glass substrate 10 only by the upper and lower air supply amount was shown, for example, glass By changing the cooling location by a method such as independently controlling the amount of air supplied from the plurality of air supply ports 16 according to the measurement results by the measuring means such as the sensor 18 at each end of the substrate 18, it is possible to precisely It is possible to perform cooling while suppressing warpage.

(Second Embodiment)
Hereinafter, the firing furnace in the second embodiment will be described with reference to the drawings. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The difference between the present embodiment and the first embodiment is a method for transporting the glass substrate 10 in the cooling chamber 7. The conveyance of the glass substrate 10 in the first embodiment is tact conveyance, whereas in the present embodiment, the glass substrate 10 is conveyed by continuous conveyance.

  FIG. 3 is a sectional view showing a firing step in the firing method according to the second embodiment of the present invention, and is a sectional view showing the lifter chamber 6 in the firing furnace 1 and the cooling chamber 7 in the vicinity of the lifter chamber 6. is there.

  The glass substrate 10 placed on the setter 11 is lowered from the upper passage 2 (not shown) by the lifter 15 and carried into the cooling chamber 7 by the roller 14 as shown in FIG. The loaded glass substrate 10 is continuously moved in the cooling chamber 7 by the roller 14.

  FIG. 3B shows a cooling step. The glass substrate 10 in this drawing is cooled by cooling air supplied from an upper air supply port 16a directly above and from a lower air supply port 16b directly below.

  FIG. 3C shows the measurement step. The glass substrate 10 in this drawing is measured by a sensor 18 directly above. The sensor 18 is basically the same as the sensor 18 used in the first embodiment, and measures the height of the surface of the glass substrate 10 below the sensor 18, and this measured value is sent to the control device 9. Sent. In this Embodiment, since the glass substrate 10 moves by continuous conveyance, a measurement may be performed continuously. The control device 9 detects the warped state of the end portion with respect to the central portion of the glass substrate 10 based on the transmitted measurement value. Based on this detection result, the increase or decrease of the cooling air from the air supply port 16 at the place where the glass substrate 10 passes next is determined.

  FIG. 3D shows a cooling control step. In this drawing, the cooling air from the upper air supply port 16a and the lower air supply port 16b immediately above the glass substrate 10 is changed according to the detection result of the measurement step, so that the direction of warping of the glass substrate 10 is relaxed. Cooling is performed. By repeatedly performing such a measurement step and a cooling control step according to the conveyance of the glass substrate 10, it is possible to cool the glass substrate 10 while reducing the warpage according to the state of the glass substrate 10. Therefore, the glass substrate 10 can be fired while suppressing distortion and cracking.

  The location of the sensor 18 is not limited to the location shown in FIG. Moreover, it is possible to measure a more precise glass shape by arranging a plurality of sensors 18 side by side in the conveyance direction of the glass substrate 10.

  According to the present invention, it is possible to cool a PDP substrate uniformly and in a short time without causing warping or cracking, which is useful for manufacturing a PDP.

Schematic sectional view showing the structure of the firing furnace in the first embodiment of the present invention Sectional drawing which shows a baking step in the baking method in the 1st Embodiment of this invention. Sectional drawing which shows a baking step in the baking method in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Firing furnace 2 Upper passage 3 Lower passage 5 Heating chamber 7 Cooling chamber 7a First cooling chamber 7b Second cooling chamber 7c Third cooling chamber 9 Control device 10 Glass substrate 11 Setter 13 Heater 14 Roller 16 Air supply port 16a Upper air supply Port 16b Lower air supply port 17 Exhaust port 17a Upper exhaust port 17b Lower exhaust port 18 Sensor

Claims (10)

A firing furnace having a heating part and a cooling part inside, and firing the glass substrate by passing the heating part and the cooling part while conveying the glass substrate mounted on the setter,
The said cooling part is provided with the cooling means and the measurement means which measures the state of the said glass substrate, The firing furnace characterized by controlling the said cooling means based on the measurement result of the said measurement means. The firing furnace according to claim 1, wherein the measuring means is a warp amount measuring means for measuring a warp amount of the glass substrate. The firing furnace according to claim 1, wherein the measuring means is a surface temperature measuring means for measuring at least one surface temperature of a glass substrate or a setter. The firing furnace according to claim 1, wherein the cooling unit includes a plurality of cooling chambers and transports a glass substrate between the cooling chambers. The cooling position on the glass substrate is changed by the cooling means of the cooling chamber located downstream in the transport direction based on the measurement by the measuring means of the cooling chamber located upstream in the transport direction. Firing furnace. A firing method of firing the glass substrate by passing a heating unit and a cooling unit while conveying a glass substrate mounted on a setter,
The said cooling part is a baking method provided with the measurement step which measures the state of the said glass substrate, and the cooling control step which controls the cooling means provided in the said cooling part based on the measurement result of the said measurement step. The firing method according to claim 6, wherein the warping amount of the glass substrate is measured in the measuring step. The firing method according to claim 6, wherein at least one surface temperature of the glass substrate or the setter is measured in the measuring step. The firing method according to claim 6, wherein the cooling unit includes a plurality of cooling chambers, and the glass substrate is tact-transferred between the cooling chambers. The firing method according to claim 9, wherein the cooling control step is performed in the cooling chamber located downstream in the transport direction based on the result of the measurement step in the cooling chamber located upstream in the transport direction.

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