TW201328818A - Glass plate-polishing device - Google Patents

Abstract

The invention provides a glass plate-polishing device. The polishing pad (26) used in the polishing device (10) of the invention is made of a soft polyurethane resin. Type A hardness is 80 or higher and density is 0.7 g/cm3 or higher. Furthermore, Type A hardness of the polishing pad (26) is 90 or less and density is 0.9 g/cm3 or less. As a result, the polishing device (10) according to the invention is able to polish a glass plate (G) using a polishing pad (26) provided with both a flattening ability and a scratch-reducing ability. Therefore, processing time can be shortened by the time that would be expended in a precision grinding process using a second polishing pad provided with only a scratch-reducing ability. Consequently, the polishing device (10) is able to significantly improve glass plate (G) polishing efficiency compared to conventional polishing devices.

Description

Glass plate grinding device

The present invention relates to a polishing apparatus for a glass sheet.

Patent Document Nos. 1, 2, and the like disclose a manufacturing apparatus for a glass plate using a floating method in which a glass plate is produced by flowing molten glass into a molten tin bath. Further, a polishing apparatus for polishing a glass plate manufactured by a floating method into a glass substrate for an FPD (Flat Panel Display) such as a liquid crystal display or an electric paste display has been known.

The glass plate manufactured by the floating method has a slight unevenness or undulation (a distance of 3 to 30 mm and a maximum height of 0.3 μm) and scratches on the surface thereof, and such minute irregularities or undulations, and Scratches are the cause of distortion or chromatic aberration in the image. Therefore, it is necessary to remove minute irregularities or undulations and scratches by the grinding device.

The polishing apparatus disclosed in Patent Document 3 holds the glass plate held on the glass holding member against the polishing pad attached to the pressure plate, and relatively moves the pressure plate and the glass holding member, thereby removing the minute glass plate. Bumps or undulations.

Further, Patent Document 4 discloses a technique of including two steps in the polishing step of the glass sheet, and using a polishing pad pair having a higher hardness (70 to 80 degrees) in the coarse grinding step of the preceding stage. The surface of the glass plate is subjected to smoothing processing, and thereafter, the polishing pad made of a resin having a low hardness (20 degrees) is used in the precision grinding step of the subsequent stage to remove the scratches existing on the surface of the glass plate. That is, the polishing apparatus of the prior glass plate is generally implemented as follows The treatment, that is, using a polishing pad of a hard resin, removes minute irregularities or undulations of the glass plate, and then removes the scratch by using a polishing pad of a soft resin to increase the polishing rate. Further, Patent Document 5 discloses that a polishing pad having a hard resin contains a urethane, and a polishing pad of a soft resin contains a foaming urethane.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2008-239370

Patent Document 2: Japanese Patent Laid-Open Publication No. 2009-46366

Patent Document 3: WO 2007/020859

Patent Document 4: Japanese Patent Laid-Open No. Hei 7-244947

Patent Document 5: Japanese Patent Laid-Open Publication No. 2009-211782

However, as in the case of the prior art polishing apparatus, when the polishing pad of the hard resin is provided with a flattening ability and the polishing pad of the soft resin is provided with the ability to suppress the scratch, the polishing pad can share the flattening ability and suppress the stroke. In the case of the traceability, the processing time required for the scratch removal of the polishing pad of the soft resin becomes long, and there is a problem that the polishing efficiency is lowered.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a polishing apparatus for a glass sheet which can improve polishing efficiency.

In order to achieve the above object, the present invention provides a polishing apparatus for a glass sheet which is obtained by polishing a glass sheet by a polishing pad made of a resin, wherein the density of the resin of the polishing pad is 0.7 g/cm ³ or more, and The A hardness of the ISO (International Organization for Standardization) 7619 is 80 or more.

Further, according to the invention, the polishing pad has an A hardness of 90 or less.

Further, according to the invention, the density of the resin of the polishing pad is 0.9 g/cm ³ or less.

Further, according to the invention, the above resin is preferably a polyurethane.

In the glass plate polishing by the polishing pad, in order to exhibit the ability to suppress scratches, for example, a soft resin urethane is preferable, but in order to exhibit flatness, the A hardness of the resin must be 80 or more.

Therefore, in the present invention, by using a soft resin as a polishing pad and setting the density of the soft resin to 0.7 g/cm ³ or more, the A hardness is 80 or more.

According to the present invention, since the glass sheet can be polished by the polishing pad having both the flattening ability and the scratch-reducing ability, it is possible to shorten the precision polishing step of the polishing pad having only the back portion capable of suppressing the scratching ability. Processing time. Thus, according to the polishing apparatus for a glass plate of the present invention, the polishing efficiency can be improved.

Further, since the upper limit of the A hardness of the resin is set to 90, the scratch resistance is further improved. In this case, the upper limit of the density of the above resin is 0.9 g/cm ³ .

Further, as the soft resin, at least one of the density and the A hardness exceeds the above upper limit, and the polishing pad having a resin having an A hardness of 80 or more and 90 or less but a density of not more than 0.7 g/cm ^{3 is used} . The experiment confirmed that the ability to suppress scratches was low.

Further, the present invention relates to a glass plate which is obtained by polishing by the above-described polishing apparatus, and has a depth of 0.1 μm or more, a width of 2 μm or more, and a length of 5 μm or more on the polished surface of the glass plate. The mark is 100 or less.

Further, in the glass plate, when the glazed height of the polished surface before polishing is 0.02 μm and the glass plate having the undulation pitch of P is polished by a grinding amount of 1 μm, the undulation height of the polished surface after the polishing is set to H, Preferably, H/P is 1.6 × 10 ^-6 or less.

According to the polishing apparatus for a glass sheet of the present invention, since the glass sheet can be polished by the polishing pad having both the flattening ability and the scratch resistance, the polishing efficiency can be improved.

Hereinafter, preferred embodiments of the polishing apparatus for a glass sheet of the present invention will be described in detail based on the accompanying drawings.

Fig. 1 is a perspective view showing the overall configuration of a polishing apparatus 10 for a glass sheet according to an embodiment. Figure 2 is a side elevational view of the polishing apparatus 10 of Figure 1.

The polishing apparatus 10 shown in the drawings is a glass plate G manufactured by a floating method, and a resin-made polishing pad 26 is used, for example, a rectangle having a thickness of 1.1 mm or less and a length of one side of 300 mm or more. The surface of the glass plate G is ground to a flatness required for the glass substrate for FPD. That is, the polishing apparatus 10 is a pair of undulating glass having a distance of 3 to 30 mm and a maximum height of 0.3 μm. The polished surface of the plate G is ground, the maximum height of the undulation is reduced to 0.05 μm or less, and the scratch is removed by grinding, thereby producing an optimum glass plate as a glass substrate for FPD which does not cause distortion or chromatic aberration to the image. Device.

In addition, the measuring method of the said undulation is the method of JIS (Japanese Industrial Standard) B0601:2001.

Further, the amount of polishing for setting the maximum height of the undulation to 0.05 μm or less is determined according to the hardness of the polishing pad 26. The higher the hardness of the polishing pad 26, the higher the flattening ability. Therefore, if the polishing amount is the above, the maximum height of the undulation can be reduced. Moreover, the lower the hardness of the resin monomer which is the material of the polishing pad 26, the more the scratch resistance can be exhibited. The polishing pad 26 will be described below.

The polishing apparatus 10 includes a polishing head 12 and a platen 14. The polishing head 12 includes a glass holding member 16 that holds the non-abrasive surface of the glass sheet G, a glass holding platen 20 on which the glass holding member 16 is attached to the intervening sheet 18, and a carrier 22 on which the glass holding platen 20 is attached. The carrier 22 is fixed to the rotary shaft 24, and by the rotating shaft 24 as its axis of rotation axis P as the _{center. 1} rotates, the rotation of the polishing head 12, and by the rotary shaft 24 to the revolution axis P ₂ is the center revolution, and the grinding head 12 is rotated and revolved.

Further, in the air chamber 23 of the carrier 22, compressed air is supplied from an air pump (not shown) via a hollow rotating shaft 24, and the pressure of the compressed air is held by the glass holding platen 20, the sheet 18, and the glass holding member. 16 is transferred to the glass plate G.

The platen 14 includes a polishing pad 26, and the spacer sheet 28 is mounted with a polishing pad 26. The polishing pad holds the platen 30, and the surface of the polishing pad 26 faces the grinding of the glass plate G. The sheet 28 is a sheet made of a resin (for example, made of a polyurethane) which is soft and has an adsorption-retaining property. The polishing pad holding platen 30 can also be swung in the in-plane direction of the surface of the polishing pad 26.

Therefore, the polishing apparatus 10 of the embodiment presses the polishing surface of the glass sheet G to the polishing pad 26 with a uniform pressure by the pressure of the compressed air, and the glass plate is rotated and revolved by the polishing head 12 Grinding surface of G is ground.

Further, the polishing apparatus 10 of the embodiment is a polishing apparatus that uses a single polishing pad 26 to polish the glass sheet G and uses compressed air (pressurized fluid), but the polishing apparatus of the present invention is not limited to the above-described polishing apparatus 10 . For example, it can also be applied to a continuous polishing apparatus in which a plurality of polishing pads are arranged to move the glass sheet G along a plurality of polishing pads arranged to polish the glass sheet G by a plurality of polishing pads.

The polishing pad 26 is made of a soft resin polyurethane, and has an A hardness (refer to ISO 7619:2004) of 80 or more [D hardness (refer to ISO 7619), 30 or more], and a density of 0.7 g/cm ³ or more. (Refer to JIS K 7222:2005). Further, the polishing pad 26 has an A hardness of 90 or less (50 or less in D hardness) and a density of 0.9 g/cm ³ or less.

In the polishing of the glass sheet G by the polishing pad 26, in order to exhibit the ability to suppress scratches, a soft resin urethane is preferable, but in order to exhibit flatness, the resin A hardness must be 80 or more.

Therefore, in the polishing apparatus 10 of the embodiment, the hardness of the polyurethane is increased by using the polyurethane of the soft resin as the polishing pad 26 and the density of the polyurethane to be 0.7 g/cm ³ or more. To 80 or more.

According to the polishing apparatus 10 of the embodiment, since the glass sheet G can be polished by the polishing pad 26 having both the flattening ability and the scratch resistance, the polishing pad having only the ability to suppress the scratching ability can be shortened (not The processing time of the finishing polishing shown in the figure). Thus, according to the polishing apparatus 10, the polishing efficiency of the glass sheet G can be remarkably improved as compared with the prior grinding apparatus.

Further, it has been found that by suppressing the upper limit of the A hardness of the resin of the polishing pad 26 to 90, the ability to suppress scratching is further improved. In this case, the upper limit of the density of the above resin is 0.9 g/cm ³ .

In other words, as a soft resin, at least one of the density and the A hardness exceeds the above upper limit, and it is confirmed by the following experiment that the scratch resistance is lowered. Further, in the same manner, the polishing pad having a resin having an A hardness of 80 or more and 90 or less and having a density of less than 0.7 g/cm ³ was confirmed to have a low scratch resistance by the following experiment.

Although the polyurethane is exemplified as the material of the soft resin, it is not particularly limited, and examples thereof include a urethane and a foamed polyurethane.

The test examples are shown below.

Figure 3 is a graph showing the density and A hardness of the polishing pad made of the foamed polyurethane of Sample Nos. 1 to 18, and the scratches on the surface of the glass plate G by the polishing of the polishing pad of each sample. The table of the list of the numbers, FIG. 4 is a table showing the correlation between the density of the samples No. 1 to 18 and the A hardness. The superiority of the polishing pad 26 of the embodiment will be described based on these tables.

The glass plate G to be evaluated is a glass plate which does not substantially contain an alkaline component, and has a size of 470 mm on the long side, 370 mm on the short side, and a thickness of 0.7. Mm.

The size of the polishing pad is a circle having a diameter of 1690 mm, and a polishing slurry supply hole for supplying the polishing slurry to the surface of the polishing pad is formed on the surface thereof, and the polishing slurry is spread over the entire surface of the polishing pad. Slot. The groove shape has a width of 1.5 mm, a pitch of 4.5 mm and a depth of 1.5 mm.

The grinding conditions were a grinding pressure of 3 kPa, a rotation speed of 50 rpm, a revolution speed of 120 rpm, a pad revolution radius of 75 mm, and a polishing slurry supply amount of 40 liters per minute. The polishing slurry is a dispersion obtained by dispersing cerium oxide with water.

The sample corresponding to the polishing pad 26 of the embodiment is referred to as a polishing pad of No. 14 to 18 of a soft resin pad. That is, the polishing pad of No. 14 has an A hardness of 86.6, a density of 0.8 g/cm ³ , a polishing pad of No. 15 having an A hardness of 85.4, a density of 0.8 g/cm ³ , and a No. 16 polishing pad A. The hardness is 84.7, the density is 0.8 g/cm ³ , the polishing pad of No. 17 has an A hardness of 85.5, the density is 0.7 g/cm ³ , and the No. 18 polishing pad has an A hardness of 86.0 and a density of 0.8 g/cm. ³ .

On the other hand, the polishing pads of Nos. 1 to 5, which are referred to as hard mats, have only the flattening ability and are used in the conventional polishing apparatus for the rough grinding step. That is, the polishing pad of No. 1 has an A hardness of 96.1, a density of 1.1 g/cm ³ , a polishing pad of No. 2 has an A hardness of 96.8, a density of 1.0 g/cm ³ , and a polishing pad of No. 3 The hardness is 96.1, the density is 0.9 g/cm ³ , the A hardness of the polishing pad of No. 4 is 94.2, the density is 0.9 g/cm ³ , the A hardness of the polishing pad of No. 5 is 95.0, and the density is 1.0 g/cm. ³ .

Further, the polishing pads of Nos. 6 and 7 which are referred to as soft mats only have the ability to suppress scratches and are used in precision polishing steps in previous polishing apparatuses. That is, the polishing pad of No. 6 had an A hardness of 37.4 and a density of 0.5 g/cm ³ , and the polishing pad of No. 7 had an A hardness of 60.0 and a density of 0.6 g/cm ³ .

Further, the polishing pad A hardness referred to as a medium elastic pad No. 8 to 13 is within the range of A hardness (80 or more and 90 or less) of the polishing pad 26 of the embodiment, but the density is less than 0.7 g/cm ³ (0.5). ~0.6 g/cm ³ ) of polishing pad. That is, the polishing pad of No. 8 has an A hardness of 88.8, a density of 0.5 g/cm ³ , a polishing pad of No. 9 has an A hardness of 86.6, a density of 0.5 g/cm ³ , and a polishing pad of No. 10 The hardness is 88.8, the density is 0.5 g/cm ³ , the polishing pad of No. 11 has an A hardness of 82.9, the density is 0.5 g/cm ³ , and the polishing pad of No. 12 has an A hardness of 84.3 and a density of 0.5 g/cm. ³ , No. 13 of the polishing pad has an A hardness of 89.8 and a density of 0.6 g/cm ³ .

According to the polishing pad No. 14 to 18 of the polishing pad 26 of the embodiment, since the A hardness is 80 or more, the flattening ability is provided, and since the density is 0.7 g/cm ³ or more and 0.9 g/cm ³ or less, As shown in the table of Fig. 3, the number of scratches remaining on the surface of the polished glass sheet G was 72, 79, 48, 70, and 91, and the number of scratches was 100 or less.

On the other hand, the number of scratches remaining on the surface of the glass sheet G polished by the hard mats Nos. 1 to 5 was 634, 10000, 10000, 178, and 214. Therefore, although the hard mat has flattening ability, it does not have the ability to suppress scratches.

Further, the number of scratches remaining on the surface of the glass sheet G polished by the soft pad of No. 6 was three. Therefore, the soft mat which does not have the flattening ability has the ability to suppress scratches.

Further, the number of scratches remaining on the surface of the glass sheet G polished by the elastic mats such as Nos. 8 to 11, 13 is 442, 1516, 528, ¹ 1 ⁴ and ⁵¹⁴ . Therefore, although the above-mentioned medium elastic pad has flattening ability, it does not have the ability to suppress scratches.

As described above, the polishing pad 26 of the embodiment in which the A hardness is 80 or more and 90 or less and the density is 0.7 g/cm ³ or more and 0.9 g/cm ³ or less is both flattening ability and scratch resistance.

Next, a method of evaluating the flattening ability of the polishing pad will be described with reference to Fig. 5 .

The lower the ratio of the undulation height/the undulation pitch of the surface of the glass plate, the higher the flattening ability of the polishing pad.

Here, the calculation method of the ratio of the undulation height/the undulation pitch will be described. When the glass plate having an undulating height of 0.02 μm and a undulation pitch of P before grinding is polished at a grinding amount of 1 μm, if the undulation height of the polished surface after grinding is H, the undulation height H is relative to The ratio of the undulation pitch P becomes H/P. The graph of Fig. 6 summarizes the relationship between the number of scratches in a piece of 470 mm × 370 mm glass sheet and H/P.

According to the table of Fig. 6, it can be seen that the ratio of the soft mat H/P is higher than the others, so the flattening ability is low, but the number of scratches is less than others. It can be seen that the ratio of the hard mat H/P is lower than the others, so the flattening ability is higher, but the number of scratches is more than others. It can be seen that the ratio of H/P is substantially the same as that of the soft resin pad corresponding to the polishing pad of the present invention, but the number of scratches is significantly larger. Further, the ratio of H/P of the soft resin pad is H/P of 1.6 × 10 ^-6 or less and 1.3 × 10 ^-6 or more, which is higher than a part of the hard pad but lower than the soft pad.

Therefore, it was found that the soft resin pad corresponding to the polishing pad of the present invention has higher flattening ability than the soft pad, and has lower flattening ability than the hard pad, but the number of scratches can be greatly reduced. .

In addition, the "scratch" described in the present specification means a depth of 0.1 μm or more, a width of 2 μm or more, and a length of 5 μm or more.

The present application is based on Japanese Patent Application No. 2011-264901 filed on Dec. 2, 2011, the content of which is hereby incorporated by reference.

10‧‧‧ grinding device

12‧‧‧ polishing head

14‧‧‧ Platen

16‧‧‧Glass holding member

18‧‧‧Sheet

20‧‧‧ glass holding platen

22‧‧‧ Vehicles

23‧‧ Air Chamber

24‧‧‧Rotary axis

26‧‧‧ polishing pad

28‧‧‧Sheet

30‧‧‧ polishing pad to maintain pressure plate

G‧‧‧glass plate

P ₁ ‧‧‧Rotary axis

P ₂ ‧‧‧ public axis

Fig. 1 is a perspective view showing an overall configuration of a polishing apparatus to which a polishing pad according to an embodiment is applied.

Figure 2 is a side view of the polishing apparatus shown in Figure 1.

Fig. 3 is a table showing the list of the density and the A hardness of the polishing pads of Sample Nos. 1 to 18.

Fig. 4 is a table showing the correlation between the density of sample Nos. 1 to 18 and the A hardness.

Fig. 5 is an explanatory view for explaining a method of evaluating the flattening ability of the polishing pad.

Fig. 6 is a table summarizing the relationship between the number of scratches in one piece of a glass plate of a specific size and H/P.

10‧‧‧ grinding device

12‧‧‧ polishing head

14‧‧‧ Platen

16‧‧‧Glass holding member

18‧‧‧Sheet

20‧‧‧ glass holding platen

22‧‧‧ Vehicles

23‧‧ Air Chamber

24‧‧‧Rotary axis

26‧‧‧ polishing pad

28‧‧‧Sheet

30‧‧‧ polishing pad to maintain pressure plate

G‧‧‧glass plate

P ₁ ‧‧‧Rotary axis

P ₂ ‧‧‧ public axis

Claims (4)

A polishing apparatus for a glass plate, wherein the glass plate is polished by a polishing pad made of a resin, wherein the resin of the polishing pad has a density of 0.7 g/cm ³ or more, and the hardness of the reference to ISO 7619 is 80. As described above, the polishing pad has an A hardness of 90 or less, and the polishing pad has a resin density of 0.9 g/cm ³ or less. A polishing apparatus for a glass plate according to claim 1, wherein the above resin is a polyurethane. A glass plate which is obtained by polishing a polishing apparatus of a glass plate according to claim 2, and having a depth of 0.1 μm or more, a width of 2 μm or more, and a length of 5 μm or more on the polished surface of the glass plate. The scratch is 100 or less. The glass plate of claim 3, wherein the undulation height of the polished surface after the grinding is set to a glazing thickness of 0.02 μm and a pacing pitch of P before grinding with a grinding amount of 1 μm H, H/P is 1.6 × 10 ^-6 or less.