JP6741394B2 - Glass substrate manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a glass substrate used for a flat panel display such as a liquid crystal display and a plasma display.

As a glass substrate used for a flat panel display (hereinafter referred to as “FPD”) such as a liquid crystal display or a plasma display, a thin glass plate having a thickness of, for example, 0.5 to 0.7 mm is used. The glass substrate for FPD has a size of, for example, 300×400 mm in the first generation, but has a size of 2850×3050 mm in the tenth generation.

In order to manufacture a large size glass substrate for FPD with such a thin plate, an overflow down draw method or a float method is preferably used. For example, Patent Document 1 discloses a method for manufacturing a glass substrate using an overflow downdraw method. That is, in Patent Document 1, a glass substrate is manufactured by sandwiching a sheet glass overflowing from a molded body by a conveying roller (pulling roller) and gradually cooling the sheet glass in the process of pulling it downward.

The plate-shaped glass substrate manufactured by such an overflow downdraw method is cut into a predetermined size. The cutting of the glass substrate is performed by forming a cutting line (cut) with a cutter or the like at the cutting position and breaking along the cutting line. Such a cutting device is disclosed in, for example, Patent Document 2 and the like.
Further, as described above, the cut end surface of the glass substrate is subjected to end surface processing such as chamfering grinding. Such an end surface processing device is disclosed in, for example, Patent Document 3 and the like.

International Publication No. 2012/132425 JP 2012-171867 A JP, 2014-087879, A

Conventionally, in the end surface processing of a glass substrate, alignment for aligning the end surface positions of the glass substrate is performed before processing. For example, when the end face processing is performed using an end face processing device (details will be described later) for performing the chamfering grinding process as shown in FIG. 4, the grinding groove 22 is formed in the glass substrate 1 aligned before the processing. The end surface is machined by the relative movement of the grinding wheel 21.

However, the alignment of the glass substrate is adjusted by pushing the end surface 1 a of the glass substrate 1 held on the transport table 30 protruding from the transport table 30. In the case of a glass substrate, since the end portion protruding from the transport table 30 is bent, it is difficult to improve the alignment accuracy. In particular, in the case of a thin glass substrate, the amount of bending of the end portion is large, it is difficult to adjust the position of the glass substrate, and alignment may not be possible.

The above-mentioned Patent Document 3 describes a method in which two pieces of position information of the end surface of the glass substrate are acquired and a grinding wheel is moved between two points connecting the positions to perform processing. Since it is difficult to accurately obtain the position information at the bent end portion, it is difficult to improve the alignment accuracy even by such a conventional method.
With the high definition of FPDs in recent years, quality requirements for glass substrates for FPDs are becoming more and more stringent, and stricter control during manufacturing is required more than ever.

Therefore, an object of the present invention is to provide a method for manufacturing a glass substrate capable of manufacturing a high-quality glass substrate, which can accurately perform the end surface processing without performing alignment before the end surface processing. To do.

As a result of intensive studies to solve the conventional technical problems, the present inventors have arrived at an invention having the following configuration.

(Invention of Structure 1)
A glass substrate manufacturing method comprising a cutting step of cutting a glass substrate formed into a plate shape into a predetermined width by a cutting means, and an end surface processing step of applying an end surface processing to an end surface of the cut glass substrate, With the glass substrate formed in a plate shape placed on the transport table, while moving the glass substrate transport path integrally with the glass substrate and the transport table, alignment of the end face before the end face processing step is performed. It is a manufacturing method of a glass substrate characterized by performing the above-mentioned cutting process and the above-mentioned end face processing process, without performing.

(Invention of Structure 2)
The glass substrate has a plate thickness of 0.3 mm or less.

(Invention of Structure 3)
3. The method of manufacturing a glass substrate according to configuration 1 or 2, wherein the transport table moves on a traveling axis provided on the glass substrate transport path.

(Invention of Structure 4)
The cutting line formed by the cutting means in the cutting step and the processing point of the end surface processing in the end surface processing step are located on the same line along the glass substrate transport path. The method for manufacturing a glass substrate according to any one of claims.

(Invention of Structure 5)
Any one of configurations 1 to 4 characterized in that at least one end of the glass substrate to be cut has an outer region having a thickness different from that of the central region of the glass substrate, and the outer region is cut and removed in the cutting step. The method for producing a glass substrate according to item.
(Invention of Structure 6)
6. The method for manufacturing a glass substrate according to any one of configurations 1 to 5, wherein the end surface processing is chamfering processing performed on an end surface of the glass substrate.

(Invention of Structure 7)
7. The method for manufacturing a glass substrate according to any one of Configurations 1 to 6, characterized in that in the end face processing step, a guide means is provided for guiding the end face of the glass substrate to an apparatus for performing the end face processing. is there.

According to the present invention, with the above configuration, the alignment before the end face processing is unnecessary, and the end face processing can be accurately performed without performing the alignment. As a result, it is possible to manufacture a high quality glass substrate.

It is a figure which shows an example of the flow of the manufacturing method of a glass substrate. It is a top view showing one embodiment of an apparatus which performs a cutting process or an end face processing process in the present invention. It is a front view showing one embodiment of an apparatus which performs a cutting process or an end face processing process in the present invention. It is a perspective view showing an example of an end face processing device used for an end face processing process.

Hereinafter, embodiments of the present invention will be described in detail.
(Overview of glass substrate manufacturing method)
FIG. 1 is a diagram showing an example of a flow of a method for manufacturing a glass substrate.
The glass substrate manufacturing method includes a melting step (ST1), a refining step (ST2), a stirring (homogenizing) step) (ST3), a supplying step (ST4), a forming step (ST5), and a cooling step ( Mainly includes ST6) and a cutting step (ST7).

In the melting step (ST1), molten glass is obtained by melting the glass raw material supplied into a melting tank (not shown). In the fining step (ST2), the molten glass is fined using a fining agent.
In the stirring (homogenization) step (ST3), the glass components are homogenized by stirring the molten glass in a stirring tank (not shown) using a rotating tool such as a stirrer.
In the supplying step (ST4), the homogenized molten glass is supplied from the stirring tank through a predetermined pipe to a molding device (not shown).

This molding apparatus is, for example, a molding apparatus by the above-mentioned overflow down draw method, and the molding step (ST5) and the cooling step (ST6) are performed.
In the forming step (ST5), the molten glass is formed into a sheet glass to make a sheet glass flow. In the case of the overflow down draw method, the flow direction of the sheet glass is vertically downward. In the cooling step (ST6), the sheet glass that has been molded and flows has a desired thickness, and is cooled so that warpage and distortion caused by cooling do not occur.
In the cutting step (ST7), the sheet glass supplied from the molding apparatus is cut into a predetermined length to obtain a plate-shaped glass substrate.

Further, the cut glass substrate is further cut into a predetermined size, and a glass substrate having a target size is manufactured. After that, the glass substrate end surface is processed (grinding, polishing, etc.) and the glass substrate is cleaned, and after the presence or absence of defects such as bubbles and striae is inspected, the glass substrate that has passed the inspection is the final product. Packed and shipped.
The present invention further includes a cutting step of cutting the glass substrate cut into the plate shape described above into a predetermined size (width) to produce a glass substrate of a target size, and after the cutting step, chamfering etc. on the glass substrate end face. The present invention relates to an improvement in a series of steps of an end surface processing step of performing a grinding process, which will be described in detail later.

The glass substrate manufactured in this embodiment is suitably used, for example, as a glass substrate for a liquid crystal display, a glass substrate for an organic EL display, and a cover glass. In addition, the glass substrate can also be used as a cover glass for a display or a casing of a mobile terminal device, a touch panel, or a glass substrate or a cover glass for a solar cell. In particular, it is suitable for glass substrates for liquid crystal displays.

Further, the widthwise and vertical lengths of the glass substrate are, for example, 500 mm to 3500 mm, preferably 1000 mm to 3500 mm, and more preferably 2000 mm to 3500 mm.

(Composition of glass substrate)
As the glass composition of the glass substrate for the above-mentioned use, aluminosilicate glass, boroaluminosilicate glass, non-alkali glass, and slightly alkaline glass, for example, the following can be preferably mentioned. In addition, the content rate display of the composition shown below is mol %.
_{SiO 2 55~75%, Al 2 O} 3 5~20%, B 2 O 3 0~15%, RO 5~20% ( wherein, R is Mg, Ca, among Sr and Ba, contained in the glass substrate all _{elements), R '2 O 0~0.4%} ( provided that, R' is Li, among the Na and K, all the elements contained in the glass substrate).
Of course, in the present invention, it is not necessary to limit the glass composition of the glass substrate, and it is optional.

Next, an apparatus preferably used in the cutting step, the end surface processing step, and the series of steps in the present invention will be described.
FIG. 2 is a plan view showing an embodiment of an apparatus for performing the cutting process or the end face processing process in the present invention. Further, FIG. 3 is a front view showing an embodiment of an apparatus for performing the cutting process or the end face processing process in the present invention.

The continuous sheet glass supplied from the above-mentioned forming apparatus by, for example, the overflow down draw method is cut into a predetermined length, and one sheet of glass is separated from the continuous sheet glass. The glass substrate 1 can be obtained by cutting and removing thick outer regions (so-called ears) formed at both ends of the separated glass. The obtained plate-shaped glass substrate 1 is transported to a cutting process while being suction-held on the transport table 30, and its four sides are cut to have a size used by a panel maker. Here, the cutting device 10 forms cutting lines at predetermined cutting positions on both ends of the substrate (cutting step).
Next, in the glass substrate 1 in which the cutting lines are formed at the cutting positions on both ends of the substrate as described above, the region outside the glass substrate 1 (the end 2 outside the product region) is broken along the cutting lines, The glass substrate is formed into a predetermined size and a target size is manufactured (edge cutting).

Next, the glass substrate 1 of the target size manufactured through the cutting process described above is further adsorbed and held on the transfer table 30 and transferred to the next end surface processing process. Here, for example, chamfering grinding is performed on the cut end surface of the glass substrate 1 by the end surface processing device 20 (end surface processing step).

In the present embodiment, the glass substrate 1 is transported between the steps while being suction-held on the transport table 30, but a particularly characteristic configuration is that the glass substrate 1 is retained on the transport table 30. The glass substrate 1 and the transport table 30 are integrally moved along the glass substrate transport path to perform the cutting process and the end face processing process. In the present embodiment, the transport table 30 is configured to move on the traveling shaft 60 provided on the glass substrate transport path. The arrow A in FIG. 2 indicates the glass substrate transport direction. The traveling shaft 60 is, for example, a rail, and the transport table 30 moves on the rail.

Next, the cutting device will be described.
The cutting device 10 includes a cutting means 11 that moves on one surface of the glass substrate 1 so as to form a cutting line at a predetermined cutting position on the glass substrate 1, and the cutting means 11 on the other surface of the glass substrate 1. And a cutting table 12 arranged so as to be opposed thereto. Here, the positional relationship between the cutting table 12 and the transport table 30 is appropriately adjusted together with the position of the cutting means 11 depending on the required product size of the glass substrate.

It is preferable that the cutting means 11 is configured to rotate and move with respect to the glass substrate surface, and specifically, a cutting tool such as a cutter wheel is suitable. The cutter wheel is illustrated in FIGS. 2 and 3.

Further, the cutting table 12 is preferably configured to move together with the movement (preferably rotational movement) of the cutting means 11. In this case, the size of the cutting table 12 may be set to a size necessary for receiving a load from the cutting means 11 and performing stable cutting. As the cutting table 12, for example, a surface plate made of SUS or a surface plate to which a resin pad (for example, urethane pad) is attached can be used. The cutting table 12 is not limited to a platen, but may be a spherical or wheel-shaped (cylindrical) member that can move with the movement of the cutting means 11 so as to face the cutting means 11. Good.

The cutting table 12 may be fixed at a predetermined position. However, in this case, since only the cutting means 11 moves, the length of the cutting table 12 (length in the substrate transfer direction) is It is necessary to make it longer than the length of the side of the glass substrate 1 along which the cutting line is formed in the carrying direction.
Alternatively, the positions of the cutting means 11 and the cutting table 12 may be fixed and the glass substrate 1 may be moved.

In addition to the cutting means 11 and the cutting table 12, the cutting device 10 includes drive means and control means (not shown) for driving and controlling these.

In the above structure, the cutting means 11 moves along a predetermined cutting position of the glass substrate 1 (for example, a position along the broken line 50 in FIG. 2) on one surface of the glass substrate 1 while applying a predetermined load. To form a cutting line. At this time, a load is applied to the surface of the glass substrate in the direction of pushing the cutting edge of the cutting means 11. On the other hand, the cutting table 12 receives a load from the cutting means 11 on the other surface of the glass substrate 1 so that a cutting line can be stably formed.

Further, when the cutting table 12 is formed of a spherical or wheel-shaped (cylindrical) member that can move with the movement of the cutting means 11, when the glass substrate 1 is cut, a load (pressing force) from the cutting means 11 is applied. Is received at the apex of the peripheral surface of the spherical or wheel-shaped member, the force applied to the cutting edge of the cutting means 11 concentrates in the vertical direction, so that a cutting line with a stable depth (cutting amount) is formed. be able to.

Next, the end face processing device 20 will be described.
FIG. 4 is a perspective view showing an example of an end face processing device used in the end face processing step. Hereinafter, description will be given with reference to FIG. 4 and FIGS. 2 and 3 described above.
The end surface processing apparatus 20 has a grinding wheel 21, which is entirely made of a cylindrical grindstone, a driving unit, a control unit, and the like, inside thereof. The grinding wheel 21 is formed with a grinding groove 22 recessed inward over the entire circumference in the horizontal direction of the grinding wheel 21. The grinding groove 22 can form a predetermined chamfered surface with respect to the end surface of the glass substrate. It has a unique shape. The grindstone forming the grinding wheel 21 may be of any type as long as it is usually used for grinding glass. The grinding wheel 21 is configured to be rotatable in the arrow direction shown in FIG. 5, for example.

The end face processing device 20 is installed so that the grinding wheels 21 face the end faces 1a on both sides of the glass substrate 1, respectively. Then, the end face processing device 20 grinds the end face 1a by pressing the rotating grinding wheel 21 toward each of the both end faces 1a of the glass substrate 1 held and moved on the transport table 30. , Chamfer. It should be noted that the movement of the glass substrate 1 is temporarily stopped, the rotating grinding wheel 21 is pressed toward both end surfaces 1a of the glass substrate 1, and the grinding wheel 21 is further moved along the end surface 1a of the glass substrate 1. It is also possible to adopt a configuration that allows it.

The guide tables 40 shown in FIGS. 2 and 3 are arranged on both sides of the transport table 30 at positions separated by a certain distance, and both end portions (both end surfaces 1a) of the glass substrate 1 are respectively subjected to the above grinding. It is a guide member for guiding to the grinding groove 22 of the wheel 21. In particular, when the glass substrate 1 is a thin plate, both ends thereof are bent, so guide members for guiding the both ends of the glass substrate 1 to the grinding wheel 21 are required. That is, the guide table 40 is a means for positioning the end portion of the glass substrate 1 in the height direction. As the guide member, for example, a floating adsorption panel made of liquid can be used. The guide table 40 can be adjusted so as to be movable in the vertical direction according to the amount of bending of both ends of the glass substrate, and both ends of the glass substrate 1 can be appropriately guided to the processing points of the grinding wheel 21. Further, the positional relationship between the guide table 40 and the transport table 30 is appropriately adjusted together with the position of the end face processing device 20 depending on the product size of the cut glass substrate.

When the processing of one end surface 1a of the glass substrate 1 is completed in this way, the glass substrate 1 is rotated by 90 degrees, and the other end surfaces of the other are processed in the same manner.

As described above, the cutting line formation, the edge cutting, and the end surface processing of the glass substrate 1 are performed. As described above, the characteristic configuration of the present embodiment is that the glass substrate 1 is a transport table. The glass substrate 1 is transported while being suction-held on the glass substrate 1, and the glass substrate 1 is held on the transport table 30, while the glass substrate 1 and the transport table 30 are integrally moved along the glass substrate transport path, and the cutting step is performed. And the end face processing step is performed. Further, in the present embodiment, in order to integrally move the glass substrate 1 and the transport table 30 along the glass substrate transport path, the transport table 30 is mounted on the traveling shaft 60 provided in the glass substrate transport path. Is configured to move.

According to the above configuration, the processing point (cutting line forming position) in the cutting step and the processing point in the end surface processing step are provided on the same line along the glass substrate transport path. That is, in the cutting step, the glass substrate 1 is moved integrally with the transfer table 30 to form a cutting line parallel to the glass substrate transfer path, and the end portion is cut along the cutting line. Then, by continuously moving the glass substrate 1 together with the transport table 30 on the glass substrate transport path, in the end face processing step, a processing point for end face processing is provided on an extension line of the cutting line forming position. , The end face will be processed. Therefore, the conventional alignment before the end surface processing is unnecessary, and the end surface processing can be performed accurately without performing the alignment. Further, the machining allowance at the time of end face machining can be reduced, and the grinding wheel 21 can be machined without applying an excessive load, so that the tool life can be extended.

In the present embodiment, the transport table 30 is configured to move on the traveling shaft 60 provided in the glass substrate transport path. However, the traveling shaft 60 has, for example, a traveling direction accuracy of ±30 μm and a height direction. It is provided with an accuracy of ±40 μm.

For example, in the step of forming the cutting line, the accuracy in the height direction of the traveling shaft 60 may affect the straightness of the cutting line. When the glass substrate 1 fluctuates in the height direction, the cutting line does not enter stably, the cutting line does not reach a desired depth, or the cutting means 11 slips and cannot form the cutting line. May occur.

On the other hand, by providing the end portion of the glass substrate 1 by a predetermined amount or more, at least 5 mm or more, for example, 30 mm or more, from the transport table 30 that sucks and holds the glass substrate 1 to transport, The vertical movement of the transport table 30 due to the straightness of the shaft 60 is absorbed in the above-mentioned protruding area, and the end surface of the glass substrate 1 is stably supported by the guide member at the processing point. It is possible to suppress the influence from being transmitted to the formation region of the.

In addition, there may be a problem that the quality of the end surface is not stable due to the end surface processing due to the undulation in the traveling direction of the traveling shaft 60. In such a case, for example, the straightness of the end surface of the glass substrate subjected to the end surface processing is measured to measure the straightness in the X-axis direction of the grinding wheel 21 (that is, in the plane of the glass substrate and orthogonal to the substrate transport direction). By performing the control, the processing accuracy can be improved and the end surface quality can be stabilized. For example, the shape of the processed end surface is measured, and based on the measured shape of the end surface, the processing line that is the locus of the grinding wheel for the glass substrate in the processing step is calculated, and based on the calculated processing line, the end surface is calculated. The adjustment line used to uniformly machine the workpiece is calculated, and when the adjustment line is calculated, control is performed in the X-axis direction so that the trajectory of the grinding wheel 21 with respect to the glass substrate follows the adjustment line, and the end surface is Processing (Japanese Patent Application No. 2014-115299 previously proposed by the applicant).

In the present invention, the glass substrate 1 has a thickness of, for example, 0.01 mm to 1.0 mm. Further, the present invention is particularly suitable for manufacturing a thin glass substrate having a plate thickness of 0.3 mm or less (for example, 0.05 to 0.3 mm).

The thinner the glass substrate, the more unstable the formation of cutting lines, and the more easily the edges bend, making it difficult to perform alignment that was performed before the conventional end face processing. The effect of the present invention is remarkable in the production of Even in the conventional end face processing of a thin glass substrate which is difficult to be aligned, it is possible to accurately process the cut end face without performing alignment. Particularly preferably, it is suitable for manufacturing a glass substrate having a plate thickness of 0.2 mm or less, and more preferably suitable for manufacturing a glass substrate having a plate thickness of 0.1 mm or less.

As described above, according to the present invention, in a state where the glass substrate formed into a plate shape is placed on the transport table, by moving the glass substrate and the transport table integrally in the glass substrate transport path, Since the cutting line formed by the cutting means in the cutting step and the processing point of the end surface processing in the end surface processing step are located on the same line along the glass substrate transport path, before the end surface processing that has been conventionally performed. No need for alignment, and end face processing can be performed accurately without alignment. As a result, it is possible to manufacture a high quality glass substrate.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications and changes may be made without departing from the scope of the present invention. is there.

(Modification)
In the above-described embodiment, the thick outer regions (so-called ears) formed at both ends of one sheet of glass separated from the continuous sheet glass supplied from the forming apparatus are first cut and removed to obtain The glass substrate 1 thus obtained is cut by the above-mentioned cutting process so as to have a predetermined size. As a modified example of such an embodiment, with respect to one piece of glass separated from the above continuous sheet glass, the so-called ears are not cut and removed first, and a predetermined product size is directly obtained. Therefore, it can be configured to be cut by the cutting step. In this case, in the cutting step, the end portion outside the product area including the ear portion is cut.

As in this modification, if the substrate is provided with ears, the rigidity of the substrate is high, and therefore it is relatively easy to handle from the single wafer cutting to the processing step. In particular, a glass substrate separated from a thin glass sheet of 0.2 mm or less is preferable because it can be handled while maintaining the rigidity of the glass by carrying and handling it to a processing device without cutting the ears.

DESCRIPTION OF SYMBOLS 1 Glass substrate 1a End surface of glass substrate 2 End part outside product area 10 Cutting device 11 Cutting means 12 Cutting table 20 End surface processing device 21 Grinding wheel 22 Grinding groove 30 Conveying table 40 Guide table 60 Travel axis

Claims (4)

A glass substrate manufacturing method comprising a cutting step of cutting a glass substrate formed into a plate shape into a predetermined width by a cutting means, and an end surface processing step of applying an end surface processing to an end surface of the cut glass substrate,
The glass substrate has a plate thickness of 0.3 mm or less,
In the end face processing step, an end face of the glass substrate is provided with guide means for guiding the device to perform the end face processing,
The guide means guides the end surface of the glass substrate after the cutting step to a processing point of an apparatus for performing the end surface processing according to the amount of bending of the end surface of the glass substrate when the guide means is not used. So that it can be moved vertically in the height direction of the end face,
Formed in a state of mounting the glass substrate which is molded in the plate on the conveyor table, the Rukoto moving the glass substrate transport path are integrally and the glass substrate and the transfer table, the cutting means in the cutting step The cutting line and the processing point of the end surface processing in the end surface processing step are located on the same line along the glass substrate transport path, and the cutting is performed without performing alignment of the end surface before the end surface processing step. A method of manufacturing a glass substrate, which comprises performing a step and the end face processing step. The method of manufacturing a glass substrate according to claim 1, wherein the transport table moves on a traveling axis provided in the glass substrate transport path. It has different outer regions of thickness with the central region of the glass substrate to at least one end of the glass substrate to be cut, the cutting process according to claim 1 or 2, characterized in that cutting and removing the outer region Method for manufacturing glass substrate. The end face processing, a glass substrate manufacturing method according to any one of claims 1 to 3, wherein the a chamfering applied to the end face of the glass substrate.

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