JP5332085B2 - Manufacturing method of glass substrate for flat panel display - Google Patents

Description

  The present invention relates to a glass substrate for a flat panel display, and more particularly to a glass substrate for a flat panel display that is subjected to a predetermined treatment while being placed on a work table.

  As is well known, with the diversification of display devices in recent years, flat panel displays (hereinafter also referred to as FPDs) such as liquid crystal displays, plasma displays, and field emission displays have become widespread. It is customary that the glass substrate for heat treatment is heat-treated during the production process. And when performing this heat processing, the method of using the setter which has a flat mounting surface, and conveying in a heating furnace in the state which mounted the glass substrate heat-processed on the setter is employ | adopted.

  Further, the glass substrate for FPD may be warped due to its manufacturing method or the like, and various measures are taken against such warpage of the glass substrate. . As a specific example, for example, in Patent Document 1 below, warpage is imparted in advance by forming chemical strengthening treatment layers having different film thicknesses on the front and back surfaces of a glass substrate for a liquid crystal display, and both ends of the glass substrate. A method for preventing the glass substrate from being bent and falling when it is supported and conveyed is disclosed. Patent Document 2 below is not directly related to the glass substrate for FPD, but the amount of warpage of the filter glass substrate used by being arranged on the surface side of the glass substrate for FPD is 1.0. A method for preventing a reduction in display quality due to warping of the filter glass substrate by setting the ratio to% or less is disclosed.

JP 2002-328362 A JP 2002-91326 A

  By the way, in the heat treatment process of the glass substrate for FPD described above, there is a case where the glass substrate is displaced with respect to the setter before being carried into the heating furnace and after being carried out from the heating furnace. It was. When such a situation occurs, there has been a problem that the glass substrate is not properly heat-treated, or the glass substrate is damaged such as scratches.

  Such a problem may occur when the mounting state of the glass substrate when the glass substrate is placed on the setter is unstable, that is, when the warp of the glass substrate when placed on the setter is inappropriate. Specifically, in a state where the glass substrate is placed on the setter, if the glass substrate warps too much, the orientation of the glass substrate on the setter becomes unstable. The glass substrate moves due to the bending of the glass substrate due to heating or the like. As a result, the glass substrate is displaced from the setter before and after the heat treatment.

  On the other hand, when the glass substrate is placed on the setter and the warpage of the glass substrate is too small or no warpage occurs, a thin air layer is interposed between the glass substrate and the setter. When the glass substrate is placed on the setter or when the setter is transported, the glass substrate slides on the setter, and in this case as well, the glass substrate is displaced relative to the setter.

  The above problem is not limited to the case where a glass substrate is placed on a setter and subjected to heat treatment, and cooling, electrode formation, exposure, etc., with the glass substrate placed on a predetermined work table. Even when various processes are performed, it can occur in the same manner. In other words, regardless of whether the workbench is movable or non-movable, if the glass substrate placed on the workbench is misaligned between the processing steps, the glass substrate may have processing defects, scratches, etc. The damage will occur as well.

  Therefore, the warpage of the glass substrate in a state where the glass substrate is placed on a workbench such as a setter is a problem whether it is too large or too small. From this viewpoint, there is no countermeasure against the warp of the glass substrate. The fact is not taken. That is, neither of the above-mentioned patent documents 1 and 2 discloses an effective measure against the warp of the glass substrate from such a viewpoint. Specifically, the above-described Patent Document 1 merely discloses that the glass substrate is warped in advance. On the other hand, Patent Document 2 discloses that the warpage amount of the glass substrate is set to 1.0% or less, particularly preferably 0.6% or less. This warpage amount is a glass for FPD. It is not a rule for a substrate, but a rule for a filter glass substrate disposed in front of the substrate. If the warp amount of 1.0% or 0.6% is given to the glass substrate for FPD, the warp becomes too large for the glass substrate for FPD, and various treatments such as heat treatment are hindered. This can cause a fatal problem that it cannot be used as a product. In particular, in the case of a glass substrate for a plasma display, the problem of positional displacement of the glass substrate with respect to the setter described above is significant, and countermeasures are desired.

  An object of the present invention is to appropriately set the amount of warpage when such a glass substrate is placed on a workbench within a range that does not impair the function as a glass substrate for a flat panel display. The purpose is to suppress the displacement of the substrate.

The present invention has been made to solve the above problems is a method for producing a glass substrate for a flat panel display, on a setter having a flat mounting surface, warpage than 0.003% 0. After placing a glass substrate for flat panel display of 050% or less, the glass substrate in this state is characterized by including a substrate processing step in which heat treatment is performed in a heating furnace . In addition, the amount of warpage here is a state in which the glass substrate is placed on the setter , the dimension in the major axis direction of the glass substrate is L, and the maximum separation distance from the setter surface to the back surface of the glass substrate is h. In this case, the numerical value is represented by h / L (%).

According to such a method , since the glass substrate for a flat panel display placed on a setter as a workbench is provided with a warp of the warp amount in the above numerical range, the position shift on the setter Can be accurately suppressed. Therefore, it becomes possible to suitably perform a heat process on a glass substrate on a setter, it is possible to reduce the probability of damage occurs such as scratches rubbing the glass substrate as much as possible. In addition , if the warp amount is within the above numerical range, even when a precise electrode or the like is formed on the glass substrate, the warp does not cause a processing failure due to the warp. Good product value as a glass substrate can be maintained.

That is, when the amount of warpage of the glass substrate is less than 0.003%, the glass substrate becomes too flat, a thin air layer is interposed between the glass substrate and the setter, and the glass substrate slips on the setter. May cause misalignment. On the other hand, if the amount of warpage of the glass substrate exceeds 0.050%, the glass substrate is excessively curved, and the posture on the setter becomes unstable, and the position is likely to be displaced. In this case, even if there is no misalignment on the setter , various precision treatments are appropriately performed due to the warpage when a precise electrode or the like is formed on the glass substrate. This may cause a processing failure. When such a situation occurs, the product value as a glass substrate for a flat panel display is reduced, as in the case where the glass substrate is displaced on the setter . It cannot be used for. Therefore, such a problem can be suitably avoided by setting the amount of warpage of the glass substrate within the above numerical range. The present invention is particularly suitable for a glass substrate for a plasma display having a glass substrate thickness of 1 mm to 3 mm and a size of 300 mm to 5000 mm × 700 mm to 5000 mm.

In the above method, the glass substrate may be transported into the heating furnace in a state of being placed on the setter .

  That is, since the positional deviation of the glass substrate with respect to the setter is regulated, the position of the glass substrate with respect to the setter is substantially different between before the glass substrate is carried into the heating furnace and after the glass substrate is carried out from the heating furnace. Are kept the same. Therefore, it is possible to appropriately perform the heat treatment on the glass substrate and reduce the probability that the glass substrate is damaged due to an unfair scratch or the like.

  In the above method, before the substrate processing step, in a forming step of forming molten glass into a plate-shaped glass substrate base material in a float bath, and in a slow cooling furnace disposed at a rear processing position of the float bath A cooling step of cooling the glass substrate base material, and in the cooling step, the surface side cooling temperature of the glass substrate base material is set lower than the back surface side cooling temperature, thereby warping in the substrate processing step. You may make it provide the curvature corresponding to quantity.

  If it does in this way, it will become possible to give the glass substrate the curvature corresponding to the amount of curvature in a substrate processing process simply and accurately by the very simple method of adjusting the cooling temperature in a slow cooling furnace.

  In this case, it is preferable to set the temperature difference between the front surface side cooling temperature and the back surface side cooling temperature to 5 ° C to 25 ° C.

  As described above, according to the glass substrate for a flat panel display according to the present invention, by setting the amount of warpage to the above numerical range, the positional deviation of the glass substrate on a workbench such as a setter is accurately suppressed. The Therefore, it is possible to properly execute a predetermined process performed on the glass substrate on the work table, and to reduce as much as possible the probability that the glass substrate will be damaged such as a scratch. Become. In addition, if the warpage is a warpage amount within the above numerical range, the precision processing is not hindered by the warpage when the precision processing such as forming precise electrodes on the glass substrate is performed. The function required for the glass substrate for panel displays can be suitably secured.

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

  1A and 1B are schematic views showing an example of a glass substrate for FPD according to an embodiment of the present invention. As shown in the figure, the glass substrate 1 for FPD is a rectangular plate having a thickness of 3.0 mm or less, and is used as a glass substrate for plasma display in this embodiment. It is. The glass substrate 1 is slightly warped with respect to the work table 2 in a state of being placed on the work table 2 having a flat placement surface. The warpage of the glass substrate 1 is expressed as h / L (%) when the dimension in the major axis direction of the glass substrate 1 is L and the maximum separation distance from the surface of the work table 2 to the back surface of the glass substrate 1 is h. When defined by the amount of warpage expressed, it is set so that 0.003% ≦ h / L ≦ 0.050%. Note that the glass substrate 1 is not limited to a glass substrate 1 that is curved in an arc shape in only one direction so as to form a part of the thin cylinder in the circumferential direction as long as the amount of warpage in the above numerical range is satisfied. It may be a shape that is curved in a shape, or a shape that is curved in an S shape so that unevenness is continuous in one direction.

  The maximum separation distance h is obtained by measuring a gap between the glass substrate 1 placed on the work table 2 and the work table 2 with a gap gauge. Specifically, the maximum separation distance h is defined as follows. For example, as shown in FIGS. 1 (a) and 1 (b), in a state where the glass substrate 1 is placed on the placement surface of the work table 2, a circle is formed only in one direction so as to protrude upward. As shown in FIGS. 2A and 2B, the maximum separation distance h in the case of exhibiting an arcuate shape is on the mounting surface of the work table 2 with the front and back surfaces of the glass substrate 1 turned upside down. It is defined by the maximum separation distance h ′ from the placement surface of the work table 2 when placed to the surface of the glass substrate 1. As shown in the figure, the maximum separation distance h ′ is obtained by measuring a gap between the work table 2 and the glass substrate 1 placed on the work table 2 with the surface side facing downward with a clearance gauge 3. Sought by. That is, the numerical range of the warpage amount (h / L) is determined based on the maximum separation distance h ′.

  Further, in the state where the glass substrate 1 is placed on the placement surface of the work table 2, the glass substrate 1 exhibits a shape curved in a bowl shape so as to be convex upward (FIGS. 3A and 3B), Similarly to the above case, the maximum separation distance h in the case of exhibiting a shape curved in an S shape so that unevenness is continuous in one direction (FIGS. 5 (a) and (b)) is the same as the surface of the glass substrate 1. It is defined by the maximum separation distance h ′ from the mounting surface of the work table 2 to the surface of the glass substrate 1 when the back surface is placed upside down on the mounting surface of the work table 2 (FIG. 4A ) And (b) or FIG. 6 (a) and (b)).

  And the glass substrate 1 to which the warpage of the warpage amount in the above numerical range was given can maintain a good contact state with the work table 2 by the warpage. For this reason, it is possible to accurately suppress the occurrence of displacement of the glass substrate 1 on the work table 2. This is particularly advantageous when the glass substrate 1 is heat treated. That is, when heat-treating the glass substrate 1 for FPD, it is customary to carry the glass substrate 1 in a state where the glass substrate 1 is placed on a work table 2 called a setter. If the warpage of the warpage amount in the above numerical range is applied, the positional deviation of the glass substrate 1 with respect to the setter 2 is regulated, and before the glass substrate 1 is carried into the heating furnace and after the glass substrate 1 is carried out from the heating furnace. Thus, the position of the glass substrate 1 with respect to the setter 2 is maintained substantially the same. Therefore, the glass substrate 1 is appropriately subjected to heat treatment, and it is possible to avoid the glass substrate 1 from being damaged such as an unfair scratch.

  Further, if the warp amount is within this numerical range, the glass substrate is not warped even in the case where a predetermined constituent film is formed in precision processing for forming a precise electrode or the like on the glass substrate 1. Similarly to the above, the difference in thickness of the constituent films hardly occurs, and the function required as a glass substrate for FPD can be suitably maintained. However, when the glass substrate is not warped, the glass substrate is likely to be displaced with respect to the work table.

  An example of the manufacturing method of the glass substrate 1 to which the curvature of the said numerical range was provided is demonstrated below.

  First, a glass raw material is melted in a glass melting furnace to obtain molten glass, and the molten glass is carried into a float bath (tin bath) and formed into a plate shape by a float method. The glass substrate base material formed into a plate shape by the float bath is carried into a slow cooling furnace, and unnecessary strain is removed. Thereafter, the glass substrate is cut into a predetermined size and subjected to a treatment such as polishing to produce a glass substrate. And in this manufacturing process, in the slow cooling furnace that cools the high temperature glass substrate base material, the surface side of the glass substrate base material (in contact with the tin of the float bath), particularly near the entrance of the slow cooling furnace facing the float bath. The ambient temperature (hereinafter referred to as the front side cooling temperature) for cooling the non-surface side), and the ambient temperature (hereinafter referred to as the back side) for cooling the back side of the glass substrate base material (the side in contact with the float bath tin). By setting the temperature lower than the cooling temperature, a warp amount in the above numerical range is given to the glass substrate 1 manufactured from the glass substrate base material. Specifically, for example, by giving a temperature difference of about 10 ° C. to the front side cooling temperature (about 600 ° C.) and the back side cooling temperature (about 610 ° C.), the warp in the above numerical range is applied to the glass substrate 1. Amount is given. In addition, the curvature amount of the glass substrate 1 can be adjusted within the said numerical range by adjusting this temperature difference within the range of 5 to 25 degreeC. That is, if the temperature difference is increased, the warp amount of the glass substrate 1 is also increased.

  As mentioned above, according to the glass substrate 1 for FPD which concerns on embodiment of this invention, when the curvature amount was set to said numerical range, position shift of the glass substrate 1 on the work benches 2, such as a setter Is accurately suppressed. Therefore, it is possible to properly execute a predetermined process performed on the work table 2 and to reduce the probability that the glass substrate is unfairly damaged such as scratches. In addition, if the warp amount is within the above numerical range, even if various precision treatments such as forming precise electrodes on the glass substrate 1 are performed, there will be no processing defects. The function required for the glass substrate for display can be suitably secured.

  In the above embodiment, the glass substrate for plasma display is applied to the present invention. However, other than this, for example, glass for various image display devices such as a liquid crystal display, an electroluminescence display, and a field emission display. The present invention can be similarly applied to a substrate or the like.

  As Examples 1 to 6 of the present invention, glass substrates having warpage amounts set to 0.003%, 0.004%, 0.005%, 0.015%, 0.017%, and 0.050%, respectively. Ten glass substrates were manufactured, and as Comparative Examples 1 and 2, ten glass substrates each having a warpage set to 0.002% and 0.052% were manufactured. Note that PP-8C manufactured by Nippon Electric Glass Co., Ltd. was used for each glass substrate. The size of each glass substrate is 1000 mm × 1000 mm, and the plate thickness is 1.8 mm.

  Then, each glass substrate is placed on a setter having a size of 1200 mm × 1200 mm, carried into a conveyor-type heating furnace, subjected to heat treatment, and the position of the glass substrate relative to the setter before being carried into the heating furnace. As a reference, the moving distance of the glass substrate carried out of the heating furnace relative to the setter was obtained as an average value of 10 samples. The heat treatment was performed under a temperature condition that the temperature was raised from room temperature to 550 ° C. over 10 minutes, kept at 550 ° C. for 10 minutes, and then cooled to room temperature over 10 minutes. In addition to the above heat treatment, a resist film was coated on each glass substrate, and the percentage of the maximum difference in film thickness with respect to the set film thickness was determined as the average value of 10 samples. These results are shown in Table 1 below.

  According to said Table 1, it can confirm that the movement distance of a glass substrate is large in the curvature amount of a glass substrate being less than 0.003%. When the moving distance is increased in this way, there is a possibility that the glass substrate has problems such as defective heat treatment and generation of scratches. Moreover, when the amount of warpage exceeds 0.050%, it can be confirmed that the thickness of the resist film varies greatly. As described above, if the film thickness of the resist film varies greatly, it becomes difficult to precisely form a predetermined element as a glass substrate for FPD. On the other hand, when the amount of warpage of the glass substrate is 0.003% or more and 0.050% or less, both the movement distance of the glass substrate and the variation of the film thickness of the resist film are small, and it is suitable as a glass substrate for FPD. It can be confirmed that In particular, if the amount of warpage of the glass substrate is 0.005% or more and 0.015 or less, the variation in the movement distance of the glass substrate and the film thickness of the resist film is preferably reduced in a balanced manner.

(A) is a perspective view which shows the glass substrate for flat panel displays which concerns on this embodiment, (b) is the longitudinal cross-sectional view. (A) is a perspective view which shows the mounting state at the time of prescribing | curing the curvature amount of the glass substrate of FIG. 1, (b) is the longitudinal cross-sectional view. (A) is a perspective view which shows another example of the glass substrate for flat panel displays which concerns on this embodiment, (b) is the longitudinal cross-sectional view. (A) is a perspective view which shows the mounting state at the time of prescribing | curing the curvature amount of the glass substrate of FIG. 3, (b) is the longitudinal cross-sectional view. (A) is a perspective view which shows another example of the glass substrate for flat panel displays which concerns on this embodiment, (b) is the longitudinal cross-sectional view. (A) is a perspective view which shows the mounting state at the time of prescribing | curing the curvature amount of the glass substrate of FIG. 5, (b) is the longitudinal cross-sectional view.

Explanation of symbols

1 Glass substrate for flat panel display 2 Work table (setter)
3 Clearance gauge

Claims (3)

A molding process for molding molten glass into a plate-shaped glass substrate base material in a float bath,
A cooling step of cooling the glass substrate base material in a slow cooling furnace disposed at a rear processing position of the float bath;
A substrate processing step of performing a heat treatment on the glass substrate obtained from the glass substrate base material,
In the cooling step, the amount of warpage of the glass substrate before the substrate processing step is set to 0.003% or more and 0.050 by setting the front side cooling temperature of the glass substrate base material lower than the back side cooling temperature. % To give a warp corresponding to the glass substrate base material,
In the substrate processing step, on a setter having a flat mounting surface, after the warp amount was placed on the glass substrate of 0.050% or less than 0.003%, the heating furnace to the glass substrate in this state method of manufacturing a glass substrate for a flat panel display, wherein the score facilities to heat treatment in. The glass substrate for a flat panel display according to claim 1 , wherein the glass substrate is transported into the heating furnace in the state of being placed on the setter in the substrate processing step. Method. Wherein in the cooling step, the temperature difference between the surface side cooling temperature and the back side cooling temperature, 5 ° C. according to claim 1 or 2, characterized in that it is set to to 25 ° C. glass for a flat panel display A method for manufacturing a substrate.

Images