Polishing device and polishing method

Abstract

To provide a polishing device and a polishing method capable of processing an end face of a glass substrate into a state having a good surface property.SOLUTION: There is provided a polishing device 100 for polishing an end surface Ga of a glass substrate G by relatively moving an outer periphery of a rotating circular polishing member 10 along an end surface Ga while bringing the outer periphery into contact with the end surface Ga. The polishing device includes: a rotation drive unit 20 that rotates a rotation shaft 21; and a chuck 30 which is provided on the rotation shaft 21 of the rotation drive unit 20 and to which the polishing member 10 is attached. The polishing member 10 has a gripping hole 11 at a center thereof, and the chuck 30 has a gripping portion 31 that grips the polishing member 10 in close contact with an inner peripheral surface of the gripping hole 11.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a polishing apparatus and a polishing method. [Background technology]

[0002] A glass substrate may crack due to defects such as scratches on the cut edge, so the edge of the glass substrate is polished.

[0003] Polishing devices that polish the edge surface of the glass substrate include those that move a polishing member such as a rotating grindstone relatively along the edge surface of the glass substrate while contacting the edge surface (see, for example, Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-126661 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-167753 [Patent Document 3] Japanese Utility Model Application Publication No. 2-31651 [Patent Document 4] International Publication No. 2011 / 113982 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-187042 Summary of the Invention [Problem to be solved by the invention]

[0005] If the polishing member is misaligned, when the edge surface of the glass substrate is polished, undulations in which minute peaks P and valleys V are periodically formed occur on the edge surface Ga of the glass substrate G, as shown in Fig. 12. In particular, if the processing speed, which is the relative movement speed between the edge surface Ga of the glass substrate G and the polishing member during processing, is increased in order to increase productivity, the undulations on the edge surface Ga of the glass substrate G become larger, as shown in Fig. 13.

[0006] If large waviness occurs on the edge surface Ga of the glass substrate G, good surface quality may not be obtained after finishing with a polishing member. For example, at the valleys V of the waviness, the contact pressure with the polishing member decreases, resulting in insufficient finishing, while at the peaks P of the waviness, the contact pressure with the polishing member increases, potentially causing peeling, burning, or fine chipping due to heat caused by a high load.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a polishing apparatus and a polishing method that can process the edge surface of a glass substrate into a good surface quality. [Means for solving the problem]

[0008] The present invention comprises the following configurations. (1) A polishing apparatus for polishing an edge surface of a glass substrate by moving a rotating circular polishing member relatively along the edge surface while bringing the outer periphery of the rotating circular polishing member into contact with the edge surface, the apparatus comprising: a rotation drive unit that rotates the rotation shaft; a chuck provided on the rotation shaft of the rotation drive unit and to which the polishing member is attached; Equipped with The polishing member has a gripping hole in the center, the chuck has a gripping portion that is in close contact with an inner circumferential surface of the gripping hole and grips the polishing member; Polishing equipment. (2) polishing the edge surface of the glass substrate using the polishing device; Polishing method. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a polishing apparatus and a polishing method that can process the edge surface of a glass substrate into a good surface quality. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a side view of a polishing apparatus according to this embodiment. [Figure 2]FIG. 2 is a schematic diagram illustrating polishing of a glass substrate by a polishing apparatus. [Figure 3] FIG. 3 is a schematic side view illustrating the polishing apparatus according to this embodiment. [Figure 4] FIG. 4 is a schematic perspective view illustrating a polishing member and a chuck of the polishing apparatus according to this embodiment. [Figure 5A] FIG. 5A is a schematic diagram of the edge surface of a polished glass substrate. [Figure 5B] FIG. 5B is a schematic diagram of the polished end face of the glass substrate. [Figure 5C] FIG. 5C is a schematic diagram of the polished end face of the glass substrate. [Figure 6] FIG. 6 is a schematic diagram illustrating the dimensions of the polishing apparatus. [Figure 7] FIG. 7 is a schematic side view illustrating a polishing apparatus according to a reference example. [Figure 8] FIG. 8 is a schematic perspective view illustrating a polishing member to which an arbor is attached and a chuck in a polishing apparatus according to a reference example. [Figure 9] FIG. 9 is a box plot showing the results of the repeatability of the peripheral runout dimension. [Figure 10] FIG. 10 is a graph showing waviness of the end face of the glass substrate polished by the polishing apparatus of Example 1. [Figure 11] FIG. 11 is a graph showing waviness of the end face of a glass substrate polished by the polishing apparatus of Example 2. [Figure 12] FIG. 12 is a schematic diagram showing waviness occurring on the edge surface of a polished glass substrate. [Figure 13] FIG. 13 is a schematic diagram showing waviness occurring on the edge surface of a polished glass substrate. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a side view of a polishing apparatus 100 according to this embodiment. Fig. 2 is a schematic view illustrating polishing of a glass substrate G by the polishing apparatus 100. Fig. 3 is a schematic side view illustrating the polishing apparatus 100 according to this embodiment. Fig. 4 is a schematic perspective view illustrating the polishing member 10 and the chuck 30 of the polishing apparatus 100 according to this embodiment.

[0012] As shown in FIGS. 1 to 4, a polishing apparatus 100 according to this embodiment includes a polishing member 10, and is an apparatus for polishing an edge face Ga of a glass substrate G by using this polishing member 10.

[0013] The polishing member 10 is a grindstone formed in a circular shape in a plan view, and has a gripping hole 11 at its center. The polishing member 10 has polishing recesses 12 on its circumferential surface. In this example, the polishing member 10 has a plurality of polishing recesses 12 arranged in the axial direction.

[0014] In the polishing apparatus 100, the edge surface Ga of the glass substrate G is brought into contact with the polishing recess 12 on the peripheral surface of the polishing member 10 which rotates in one rotation direction R, and the polishing member 10 and the glass substrate G are moved relatively in the feed direction X along the edge surface Ga of the glass substrate G, thereby polishing and chamfering the edge surface Ga, which is the cut surface (see FIG. 2).

[0015] 5A to 5C are schematic diagrams showing the shape of an end face Ga of a glass substrate G polished by the polishing apparatus 100. As shown in FIG. 5A, by polishing using the polishing recess 12 of the polishing member 10, the end face Ga of the glass substrate G is polished to an arc-shaped cross section, and both corners C1 and C2 are chamfered. In this example, the apex T of the end face Ga and both corners C1 and C2 are formed into arc-shaped cross sections with different radii of curvature. This removes defects such as scratches on the end face Ga and suppresses the occurrence of cracks. Note that the shape of the end face Ga is not limited to the above example. For example, the end face Ga may be polished so that the apex T and both corners C1 and C2 are planar, as shown in FIG. 5B. Alternatively, the end face Ga may be polished so that the apex T is planar and both corners C1 and C2 are arc-shaped, as shown in FIG. 5C.

[0016] The polishing apparatus 100 includes a rotary drive unit 20 and a chuck 30 (see FIG. 3). The rotary drive unit 20 includes a rotary shaft 21, which is rotated by a drive motor (not shown). In this example, the rotary drive unit 20 has the rotary shaft 21 extending downward from its bottom.

[0017] The chuck 30 grips the polishing member 10 and is attached to the lower end of the rotary shaft 21, for example, by bolting. The chuck 30 has a chuck body 32 and a circular gripping portion 31 with a smaller diameter than the chuck body 32. The gripping portion 31 is provided at the lower end of the chuck body 32 and grips the polishing member 10. The chuck 30 may have a flange that protrudes outward from the lower end of the chuck body 32 where the gripping portion 31 is provided. In this case, the polishing member 10 to be gripped by the gripping portion 31 can be fastened to the flange and fixed.

[0018] In this example, the runout dimension of the polishing member 10 held by the chuck 30 is preferably 1 μm or more on its periphery. If the runout dimension of the polishing member 10 held by the chuck 30 is 1 μm or less, the runout is too small, which increases the grinding wheel load too much, and there is a risk that good sharpness cannot be maintained. In contrast, the runout dimension of the polishing member 10 is preferably 20 μm or less, and more preferably 10 μm or less. If the runout dimension of the polishing member 10 held by the chuck 30 is 20 μm or more, waviness will become large, which may affect the quality of the product. Therefore, if the runout dimension of the polishing member 10 held by the chuck 30 is 1 μm to 20 μm, the edge surface Ga of the glass sheet G can be polished well while suppressing waviness.

[0019] A hydraulic chuck or a collet chuck is used as the chuck 30. A hydraulic chuck uses hydraulic pressure to elastically deform a bulging region on the outer periphery of the gripping portion 31, causing the outer periphery to bulge radially outward, and the outer periphery of the gripping portion 31 is brought into even contact with the inner periphery of the gripping hole 11 of the polishing member 10, thereby gripping the polishing member 10 with high precision. A collet chuck has a gripping portion 31 consisting of a cylindrical collet divided into multiple sections in the circumferential direction, and a drawbar is drawn into the center of the collet to expand its diameter, bringing the outer periphery into even contact with the inner periphery of the gripping hole 11 of the polishing member 10, thereby gripping the polishing member 10 with high precision. In the case of a collet chuck, the bulging region that is in close contact with the inner periphery of the gripping hole 11 of the polishing member 10 extends along the entire length of the collet.

[0020] The chuck 30 has an actuation screw 33, and by operating this actuation screw 33 (see FIG. 4), the polishing member 10 is attached to or detached from the gripping portion 31 of the chuck 30. In the case of a hydraulic chuck, by operating the actuation screw 33, a piston (not shown) is advanced or retreated, adjusting the hydraulic pressure filled in the internal flow path, and the polishing member 10 is attached to or detached from the gripping portion 31 of the chuck 30. In the case of a collet chuck, by operating the actuation screw 33, a draw bar is advanced or retreated, and the diameter of the gripping portion 31, which is made of a collet, is expanded or contracted, and the polishing member 10 is attached or detached.

[0021] Next, the dimensions of the polishing member 10 and the gripping portion 31 of the chuck 30 will be described. FIG. 6 is a schematic diagram showing the dimensions of the polishing member 10 and the gripping portion 31 of the chuck 30. As shown in FIG. In FIG. 6, the symbols represent the following dimensions. D1: outer diameter of the polishing member 10 D2: Inner diameter of the polishing member 10 T: Thickness of the polishing member 10 d: outer diameter of the gripping portion 31 h: Axial length of the gripping portion 31 H: Clamping allowance by the bulging region 31a of the gripping portion 31 L: Clearance between the inner peripheral surface of the gripping hole 11 and the outer peripheral surface of the gripping portion 31

[0022] In the polishing apparatus 100 according to this embodiment, the following dimensional relationships (1) to (3) are established. (1) The ratio H / T of the clamping allowance H of the gripping portion 31, which is in close contact with the inner circumferential surface of the gripping hole 11, to the thickness T of the polishing member 10 is 0.02 or more. With this dimensional relationship, the gripping portion 31 can grip the polishing member 10 without rattle. The clamping allowance H refers to a bulging region on the outer circumferential portion of the gripping portion 31 that is elastically deformed. (2) The ratio D2 / D1 of the inner diameter D2 of the polishing member 10 to the outer diameter D1 of the polishing member 10 is 0.01 or more. With this dimensional relationship, the polishing member 10 can polish the edge surface Ga of the glass substrate G well. (3) The clearance L between the inner peripheral surface of the gripping hole 11 and the outer peripheral surface of the gripping portion 31 is 0.001 mm or more and 0.2 mm or less. This dimensional relationship ensures good workability in attaching the polishing member 10 to the gripping portion 31, while allowing the gripping portion 31 to grip the polishing member 10 well.

[0023] In the polishing apparatus 100, the tip of the gripping portion 31 of the chuck 30 may be straight, have a diameter equal to that of the rest of the gripping portion, have a stepped portion with a smaller diameter than the rest of the gripping portion, or have a tapered portion. The tip of the gripping portion 31 is, for example, a portion approximately 5 mm from the tip surface. If the tip is stepped, the smaller diameter portion is preferably approximately 0.2 mm smaller than the rest of the gripping portion. Even if the tip is tapered, the outer diameter at the tip surface is preferably approximately 0.2 mm smaller than the rest of the gripping portion. If the tip of the gripping portion 31 is tapered, its outer peripheral surface may not necessarily be tapered, sloping linearly in cross section, but may also be arc-shaped in cross section. In particular, the stepped or tapered shape of the tip of the gripping portion 31 facilitates insertion of the gripping portion 31 into the gripping hole 11 of the polishing member 10, improving the ease of attaching the polishing member 10 to the gripping portion 31.

[0024] Next, a case where the edge surface Ga of the glass substrate G is polished by the polishing apparatus 100 having the above configuration will be described.

[0025] (gripping process) The polishing member 10 is placed in the chuck 30 so that the gripping portion 31 of the chuck 30 is inserted into the gripping hole 11. In this state, the actuation screw 33 of the chuck 30 is operated to hydraulically expand the outer periphery of the gripping portion 31, so that its outer periphery is brought into close contact with the inner periphery of the gripping hole 11. This allows the chuck 30 to grip the polishing member 10. If a collet chuck is used as the chuck 30, the polishing member 10 is placed so that the gripping portion 31 made of a collet is inserted into the gripping hole 11, and the actuation screw 33 of the chuck 30 is operated to pull the drawbar into the center of the gripping portion 31 made of a collet, expanding the diameter of the gripping portion 31 and bringing its outer periphery into close contact with the inner periphery of the gripping hole 11. This allows the chuck 30 to grip the polishing member 10.

[0026] (polishing process) The polishing member 10 is rotated by rotating the rotary shaft 21 using the rotary drive unit 20, and the edge surface Ga of the glass substrate G is brought into contact with the polishing recess 12 on the circumferential surface of the polishing member 10. Then, the polishing member 10 and the glass substrate G are moved relatively in the feed direction X along the edge surface Ga of the glass substrate G (see FIG. 4). At this time, the processing speed for moving the edge surface Ga of the glass substrate G and the polishing member 10 relatively is set to 0.1 m / min to 50 m / min. The edge surface Ga of the glass substrate G polished in this manner by the polishing apparatus 100 is polished into an arc shape in cross section, and both corners C1 and C2 are chamfered (see FIG. 5). The processing speed is preferably 1 m / min or more, and more preferably 10 m / min or more.

[0027] Here, a reference example will be described. Fig. 7 is a schematic side view illustrating a polishing apparatus 200 according to a reference example. Fig. 8 is a schematic perspective view illustrating a polishing member 10 to which an arbor 50 is attached and a chuck 40 in the polishing apparatus 200 according to the reference example.

[0028] 7 and 8, in a polishing apparatus 200 according to a reference example, a polishing member 10 is gripped by a commonly used chuck 40. The chuck 40 has a gripping portion 41, and the polishing member 10 is gripped by this gripping portion 41.

[0029] An arbor 50 is attached to the polishing member 10. The arbor 50 has a disk-shaped fixed plate portion 51 fixed to the upper surface of the polishing member 10, and a rod 52 extending upward from the center of the fixed plate portion 51.

[0030] The gripping portion 41 of the chuck 40 has a chuck hole 42 into which the rod 52 of the arbor 50 is inserted. The chuck 40 grips the rod 52 by elastically deforming the inner periphery of the chuck hole 42 using hydraulic pressure, causing it to bulge radially inward.

[0031] As described above, in the polishing apparatus 200 according to the reference example, the chuck 40 grips the polishing member 10 via the arbor 50 fixed to the polishing member 10. Therefore, the polishing member 10 gripped by the chuck 40 has a large runout dimension on its periphery.

[0032] In contrast, the polishing apparatus 100 according to this embodiment has a structure in which the polishing member 10 is gripped by the chuck 30 by bringing the gripping portion 31 of the chuck 30 into close contact with the inner peripheral surface of the gripping hole 11 in the center of the polishing member 10. Therefore, compared to the polishing apparatus 200 in which an arbor 50 is fixed to the polishing member 10 and a chuck 40 grips the rod 52 of the arbor 50 from the outer peripheral side, the structure can be simplified while increasing the gripping accuracy of the polishing member 10, and the repeatability when gripping is also improved.

[0033] This suppresses runout of the polishing member 10 relative to the center of rotation, and suppresses the occurrence of waviness when the edge surface Ga of the glass substrate G is polished by the polishing member 10. Therefore, even if the processing speed is increased to increase productivity, a good finish can be achieved, and the edge surface Ga of the finished glass substrate G can have good surface properties.

[0034] In particular, the chuck 30 is structured so that the gripping portion 31 expands radially outward by hydraulic pressure to fit closely to the inner circumferential surface of the gripping hole 11 of the polishing member 10, and thus the polishing member 10 can be easily gripped by hydraulically expanding the gripping portion 31 radially outward. Furthermore, the gripping portion 31 can be made to fit evenly to the inner circumferential surface of the gripping hole 11 in the circumferential direction, enabling more precise gripping. Even when a collet chuck, in which the gripping portion 31 made of a collet expands in diameter to fit closely to the inner circumferential surface of the gripping hole 11 of the polishing member 10, is used as the chuck 30, the gripping portion 31 can be made to fit evenly to the inner circumferential surface of the gripping hole 11 in the circumferential direction, enabling highly precise gripping.

[0035] Moreover, the outer circumferential runout of the polishing member 10 held by the chuck 30 is suppressed to 20 μm or less, particularly 10 μm or less, so that it is possible to suppress the occurrence of waviness when polishing the edge surface Ga of the glass substrate G with the polishing member 10. This allows for a good finish even when the processing speed is increased.

[0036] Furthermore, according to the polishing method for polishing the edge surface Ga of the glass substrate G using the polishing apparatus 100, the gripping accuracy of the polishing member 10 by the chuck 30 can be improved, thereby suppressing runout of the polishing member 10 relative to the center of rotation and reducing the occurrence of waviness when the edge surface Ga of the glass substrate G is polished. Therefore, at a processing speed of 0.1 m / min to 50 m / min, the edge surface Ga of the glass substrate G after finishing can be made to have good surface quality. In other words, at a wide range of processing speeds from low to high, the occurrence of waviness when the edge surface Ga of the glass substrate G is polished by the polishing member 10 can be reduced. In particular, even when the processing speed is increased to, for example, 25 m / min or higher to increase productivity, the edge surface Ga of the glass substrate G after finishing can be made to have good surface quality. In other words, a glass substrate G whose edge surface Ga has good surface quality can be obtained while increasing productivity at a high processing speed.

[0037] In the above embodiment, an example is given of polishing the end face Ga of a glass substrate G that is rectangular in plan view, but the glass substrate G to be polished is not limited to being rectangular in plan view and may be of other shapes such as a circular shape. [Example]

[0038] The polishing apparatus of Example 1 (polishing apparatus 100 of the embodiment) and the polishing apparatus of Example 2 (polishing apparatus 200 of the reference example) were evaluated for the peripheral runout dimension, the repeatability of the peripheral runout dimension, the waviness of the edge face of the glass substrate, the surface quality of the edge face of the glass substrate, the roughness of the edge face of the glass substrate, and the cullet occupancy rate. Note that Example 1 is an embodiment, and Example 2 is a comparative example.

[0039] (Evaluation of peripheral runout dimensions) (1) Evaluation method The polishing members were held by the polishing apparatus of Example 1 and the polishing apparatus of Example 2, and the runout dimension of the outer periphery of the polishing member was measured and evaluated using a dial gauge. The runout dimension measurement was carried out for each of the three polishing members A to C.

[0040] (2) Evaluation results The evaluation results of peripheral runout dimensions are shown in Table 1.

[0041] [Table 1]

[0042] As shown in Table 1, in Example 1, the peripheral runout was kept within 10 μm for all of the polishing members A to C. In contrast, in Example 2, the peripheral runout exceeded 10 μm for all of the polishing members A to C. Thus, in Example 1, the gripping accuracy of the polishing members was improved.

[0043] (Evaluation of repeatability of peripheral runout dimensions) (1) Evaluation method The polishing members were repeatedly gripped by the polishing apparatus of Example 1 and the polishing apparatus of Example 2, and the peripheral runout dimensions of the polishing members were measured and evaluated using a dial gauge. The polishing member A used in the evaluation of the peripheral runout dimensions was used as the polishing member, and this polishing member A was gripped repeatedly 10 times.

[0044] (2) Evaluation results FIG. 9 is a box plot showing the minimum, first quartile, second quartile, third quartile, maximum and average values of the peripheral runout dimensions, with the average value indicated by an x. As shown in Figure 9, in Example 1, the peripheral runout was reduced, and the variation in the peripheral runout dimension during repeated gripping was also reduced. In contrast, in Example 2, the peripheral runout dimension was large, and the variation in the peripheral runout dimension during repeated gripping also increased. Thus, in Example 1, the gripping accuracy of the polishing member was improved, and stable and accurate gripping was possible even when gripped repeatedly.

[0045] (Evaluation of glass substrate edge surfaces after polishing) (1) Evaluation method The polishing member A was held by the polishing apparatus of Example 1 and the polishing apparatus of Example 2 to polish the edge face Ga of the glass substrate G, and the waviness (μm) of the edge face Ga, the surface roughness Ra (μm) at the top T of the edge face Ga, and the cullet occupancy rate (cullet evaluation) were evaluated. The processing speeds when polishing the edge face Ga were 25 m / min and 35 m / min.

[0046] (2) Evaluation results The results of each evaluation are shown in Table 2. 10 shows the waviness of the edge surface Ga of the glass substrate G polished by the polishing apparatus of Example 1, and FIG. 11 shows the waviness of the edge surface Ga of the glass substrate G polished by the polishing apparatus 200 of Example 2. As shown in FIG.

[0047] [Table 2]

[0048] As shown in Table 2, in Example 1, the polishing scar PV value of the waviness having peaks P and valleys V on the end surface Ga was 8 μm at both a processing speed of 25 m / min and a processing speed of 35 m / min. Thus, in Example 1, waviness was suppressed at both a processing speed of 25 m / min and a processing speed of 35 m / min (see FIG. 10). In contrast, in Example 2, the polishing scar PV value of the waviness having peaks P and valleys V on the end surface Ga was 25 μm at a processing speed of 25 m / min and 34 μm at a processing speed of 35 m / min. Thus, in Example 2, relatively large waviness occurred at both a processing speed of 25 m / min and a processing speed of 35 m / min (see FIG. 11).

[0049] In Example 1, the surface roughness Ra at the top T of the end face Ga was 0.06 μm at a processing speed of 25 m / min and 0.0769 μm at a processing speed of 35 m / min. Thus, in Example 1, the end face Ga after polishing had smooth and good surface properties at both processing speeds of 25 m / min and 35 m / min. In contrast, in Example 2, the surface roughness Ra at the top T of the end face Ga was 0.096 μm at a processing speed of 25 m / min and 0.2617 μm at a processing speed of 35 m / min. Thus, in Example 2, at both processing speeds of 25 m / min and 35 m / min, the end face Ga after polishing had surface properties in which rough spots were observed in some places compared to Example 1.

[0050] Furthermore, the cullet evaluation at the top T of the end face Ga in Example 1 was graded A (occupancy rate less than 4%) at both a processing speed of 25 m / min and a processing speed of 35 m / min. In contrast, the cullet evaluation at the top T of the end face Ga in Example 2 was graded B (occupancy rate 4% or more and less than 8%) at a processing speed of 25 m / min, and graded C (occupancy rate 8% or more) at a processing speed of 35 m / min.

[0051] As described above, in Example 1, in which the chuck 30 was used, which gripped the polishing member 10 from the inner periphery by closely contacting the outer periphery of the gripping portion 31 with the gripping hole 11, waviness on the edge surface Ga of the glass substrate G after polishing was suppressed at both the high-speed processing speed (25 m / min) and the even higher processing speed (35 m / min). This resulted in an edge surface Ga with good surface texture and a reduced cullet rate. In contrast, in Example 2, in which the chuck 40 was used, in which the arbor 50 was fixed to the polishing member 10 and the rod 52 of the arbor 50 was gripped from the outer periphery by the gripping portion 41, waviness on the edge surface Ga of the glass substrate G after polishing was increased at both the high-speed processing speed (25 m / min) and the even higher processing speed (35 m / min). In particular, in Example 2, the surface texture of the edge surface Ga became rough and the cullet rate increased at the even higher processing speed (35 m / min).

[0052] From the above, according to Example 1, in the finish polishing, it is possible to use a polishing member for finishing that could not be used due to the large waviness of the end face Ga, and further quality improvement can be achieved. In addition, by suppressing the waviness, the yield rate can be improved. It was found that the same level of quality can be obtained whether the high processing speed (e.g., 25 m / min) or an even higher processing speed (e.g., 35 m / min) is used.

[0053] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0054] As described above, the present specification discloses the following: (1) A polishing apparatus for polishing an edge surface of a glass substrate by moving a rotating circular polishing member relatively along the edge surface while bringing the outer periphery of the rotating circular polishing member into contact with the edge surface, the apparatus comprising: a rotation drive unit that rotates the rotation shaft; a chuck provided on the rotation shaft of the rotation drive unit and to which the polishing member is attached; Equipped with The polishing member has a gripping hole in the center, The chuck has a gripping portion that grips the polishing member by being in close contact with the inner peripheral surface of the gripping hole. This polishing device has a structure in which the polishing member is gripped by the chuck by tightly contacting the gripping portion of the chuck with the inner surface of the gripping hole in the center of the polishing member. Therefore, compared to devices that have an arbor fixed to the polishing member and a chuck that grips the arbor rod from the outer periphery, the structure can be simplified while increasing the gripping accuracy of the polishing member, and the repeatability when gripping is also improved. This suppresses runout of the polishing member relative to the center of rotation and suppresses waviness when polishing the edge of the glass substrate with the polishing member. Therefore, even if the processing speed is increased to increase productivity, a good finish can be achieved, and the edge of the finished glass substrate can have good surface quality.

[0055] (2) The polishing device according to (1), wherein the ratio H / T of the clamping allowance H of the gripping portion that is in close contact with the inner circumferential surface of the gripping hole to the thickness T of the polishing member is 0.02 or more. According to this polishing device, the polishing member can be gripped by the gripping portion without any rattle.

[0056] (3) The polishing apparatus according to (1) or (2), wherein the ratio D2 / D1 of the inner diameter D2 of the polishing member to the outer diameter D1 of the polishing member is 0.01 or more. According to this polishing apparatus, the edge surface of the glass substrate can be polished well by the polishing member.

[0057] (4) The polishing device according to any one of (1) to (3), wherein the clearance L between the inner peripheral surface of the gripping hole and the outer peripheral surface of the gripping portion is 0.001 mm or more and 0.2 mm or less. According to this polishing device, the polishing member can be satisfactorily gripped by the gripping portion while ensuring good workability in attaching the polishing member to the gripping portion.

[0058] (5) A polishing device described in any one of (1) to (4), wherein the tip of the gripping portion is straight with the same diameter as the other portions, stepped with a portion with a smaller diameter than the other portions, or tapered. According to this polishing device, in particular, by making the tip of the gripping portion stepped or tapered, the gripping portion can be easily inserted into the gripping hole of the polishing member, improving the ease of attaching the polishing member to the gripping portion.

[0059] (6) A polishing device described in any one of (1) to (5), wherein the chuck is a hydraulic chuck that uses hydraulic pressure to expand the gripping portion radially outward to bring it into close contact with the inner surface of the gripping hole of the polishing member, or a collet chuck that pulls a drawbar into the center of the gripping portion, which consists of a cylindrical collet divided into multiple parts circumferentially, to expand its diameter and bring it into close contact with the inner surface of the gripping hole of the polishing member. In this polishing device, in the case of a hydraulic chuck, the gripping portion can be expanded radially outward by hydraulic pressure, making it possible to easily grip the polishing member. In the case of a collet chuck, the gripping portion, which is made of a collet, can be expanded in diameter by retracting the drawbar, making it possible to easily grip the polishing member. With these hydraulic chucks or collet chucks, the gripping portion can be brought into uniform contact with the inner circumferential surface of the gripping hole along the circumferential direction, enabling more precise gripping.

[0060] (7) The edge surface of the glass substrate is polished by the polishing apparatus according to any one of (1) to (6). Polishing method.

[0061] (8) The polishing method according to (7), wherein the processing speed for moving the edge surface of the glass substrate and the polishing member relative to each other is 0.1 m / min or more. According to this polishing method, by setting the processing speed to 0.1 m / min or more, it is possible to suppress the generation of waviness when polishing the edge surface of a glass substrate with a polishing member over a wide range of processing speeds from low to high. In particular, by performing processing at high speed while suppressing waviness, it is possible to obtain a glass substrate whose edge surface is finished with good surface texture while increasing productivity at a high processing speed. [Explanation of symbols]

[0062] 10. Abrasive material 11 Gripping hole 20 Rotation drive unit 21 Rotation axis 30 Chuck 31 Gripping part 100 Polishing equipment G Glass substrate Ga end face

Claims

1. A polishing apparatus that polishes an edge surface of a glass substrate by moving a rotating circular polishing member relatively along the edge surface while bringing the outer periphery of the rotating circular polishing member into contact with the edge surface, a rotation drive unit that rotates the rotation shaft; a chuck provided on the rotation shaft of the rotation drive unit and to which the polishing member is attached; Equipped with The polishing member has a gripping hole in the center, the chuck has a gripping portion that is in close contact with an inner circumferential surface of the gripping hole and grips the polishing member; Polishing equipment.

2. a ratio H / T of a clamping allowance H of the gripping portion in close contact with the inner circumferential surface of the gripping hole to a thickness T of the polishing member is 0.02 or more; The polishing apparatus according to claim 1 .

3. the ratio D2 / D1 of the inner diameter D2 of the polishing member to the outer diameter D1 of the polishing member is 0.01 or more; The polishing apparatus according to claim 1 .

4. The clearance L between the inner peripheral surface of the gripping hole and the outer peripheral surface of the gripping portion is 0.001 mm or more and 0.2 mm or less. The polishing apparatus according to claim 1 .

5. The tip of the gripping portion is straight and has the same diameter as the other portions, stepped and has a smaller diameter than the other portions, or tapered and gradually narrowed. The polishing apparatus according to claim 1 .

6. The chuck is a hydraulic chuck in which the gripping portion is expanded radially outward by hydraulic pressure to fit closely to the inner peripheral surface of the gripping hole of the polishing member, or a collet chuck in which a draw bar is drawn into the center of the gripping portion, which is made of a cylindrical collet divided into a plurality of parts in the circumferential direction, to expand the diameter of the gripping portion and fit closely to the inner peripheral surface of the gripping hole of the polishing member. The polishing apparatus according to claim 1 .

7. The end surface of the glass substrate is polished by the polishing apparatus according to any one of claims 1 to 6. Polishing method.

8. a processing speed at which the end surface of the glass substrate and the polishing member are moved relative to each other is set to 0.1 m / min or more; The polishing method according to claim 7.

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