Method for measuring flatness of glass plate

Abstract

The invention provides a method for measuring the flatness of a glass plate. The flatness of the glass plate can be measured with high precision even if the glass plate is thin. A method for measuring the flatness of a glass plate (G), in which the glass plate (G) is bent in a convex or concave arc shape, a stylus (13) of a measuring device (10) is brought into contact with the surface of the glass plate (G), and the glass plate (G) and the stylus (13) are moved relative to each other in a measuring direction (X) intersecting the bending direction (Y) of the glass plate (G) and along the main surface of the glass plate (G).

Description

TECHNICAL FIELD

[0001] The present application relates to a method for measuring flatness of a glass sheet. BACKGROUND

[0002] In Patent Literature 1, a technique is disclosed in which a pattern having periodicity of bright and dark is irradiated from a surface light source to a glass sheet, the pattern transmitted through the glass sheet is captured by a CCD camera, and a signal processing device evaluates the surface shape of the glass sheet based on the deviation of the bright and dark period in the captured image. In addition, as a method for measuring flatness of a glass sheet, a contact type is also known in which a contact measuring machine is moved while being in contact with the surface of a glass sheet, and the flatness is calculated based on the surface shape of the glass sheet measured by the contact measuring machine.

[0003] PRIOR ART DOCUMENTS PATENT LITERATURE Patent Literature 1: Japanese Patent No. 3411829

[0004] PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] However, in the flatness measurement method based on the contact type, the glass sheet is placed on a stage, and the stylus of the contact measuring machine is moved while being in contact with the surface of the glass sheet. However, particularly in the case of a thin glass sheet having a thickness of 0.5 mm or less which is easily deformed, the glass sheet placed on the stage is affected by the surface shape of the stage, and thus it is difficult to measure the flatness of the glass sheet itself. SUMMARY

[0006] Therefore, an object of the present application is to provide a method for measuring flatness of a glass sheet, which can measure the flatness with high accuracy even for a thin glass sheet.

[0007] MEANS FOR SOLVING THE PROBLEMS

[0008] The present application is configured by the following structure.

[0009] A method for measuring flatness of a glass sheet, the flatness of the glass sheet being measured, wherein the glass sheet is bent to be configured in an arc shape which is convex or concave toward the side of a stylus of a measuring device, the stylus is brought into contact with the surface of the glass sheet, the glass sheet and the stylus are relatively moved in a direction intersecting the bending direction of the glass sheet and along the main surface of the glass sheet.

[0010] EFFECTS OF THE INVENTION

[0011] According to the present application, it is possible to provide a method for measuring flatness of a glass sheet, which can measure the flatness with high accuracy even for a thin glass sheet. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic side view of a clamping member provided with a glass plate, which illustrates the measuring method of the first embodiment. Figure 2 is Figure 1 II-II sectional view in Figure 3 is a graph showing flatness of a glass plate measured by the measuring method of the first embodiment. Figure 4 is a graph showing flatness of a glass plate measured by being provided on a platform. Figure 5 is a schematic front view of a clamping member provided with a glass plate, which illustrates the measuring method of the second embodiment. Figure 6 is Figure 5 VI-VI sectional view in Figure 7 is Figure 6 VII-VII sectional view in

[0013] Explanation of Reference Numerals 10 measuring apparatus 13 stylus 21 curved portion 23 support member 25 clamping member 41 support portion 43 support member 45 locking pin 47 locking member G glass plate Ga side edge portion Gb end edge portion X measuring direction Y bending direction DETAILED DESCRIPTION

[0014] Hereinafter, an embodiment of the present application will be described in detail with reference to the drawings.

[0015] (First Embodiment)

[0016] First, the first embodiment will be described.

[0017] Figure 1 is a schematic side view of a clamping member 20 provided with a glass plate G, which illustrates the measuring method of the first embodiment. Figure 2 is Figure 1 II-II sectional view in

[0018] As Figure 1 and Figure 2The flatness measurement method of the first embodiment is a method of measuring the flatness of the surface of the glass plate G. The glass plate G as a measurement object is, for example, a thin glass plate having a thickness of about 0.5 mm or less, for example, a glass plate for a flat panel display (FPD) such as an LCD (Liquid Crystal Display) or an OLED (Organic Light-Emitting Diode). The glass plate G is formed in a plan view rectangular shape having a pair of side edge portions Ga and a pair of end edge portions Gb.

[0019] In the flatness measurement method of the first embodiment, a contact-type measurement device (for example, SURFCOM manufactured by Tokyo Seimitsu Co., Ltd.) 10 is used. The measurement device 10 is provided with a probe 11 having a stylus 13 at a distal end portion, and the probe 11 is supported to a device main body (not shown). The measurement device 10 measures the flatness of the surface of a measurement object by relatively moving the stylus 13 with respect to the measurement object while moving the probe 11 with respect to the device main body in a length direction, in a state in which the stylus 13 is in contact with the surface of the measurement object.

[0020] In the first embodiment, the clamping member 20 is used when measuring the flatness of the glass plate G. The clamping member 20 is provided with a pair of support members 23 and a plurality of clamping members 25.

[0021] The support members 23 are formed in a plate shape or a block shape, and an upper portion thereof is formed in a curved portion 21 curved in an arc shape protruding in the length direction. The support members 23 are disposed at intervals from each other on an upper surface of a base 27.

[0022] The clamping members 25 are formed in a U shape having a locking piece 31 and a holding piece 33. The clamping members 25 are fitted to the curved portions 21 of the support members 23 in a state in which the holding pieces 33 are disposed on the upper surface side of the support members 23, by locking the locking pieces 31 with respect to the support members 23 from the side thereof. The clamping members 25 are fitted to a plurality of portions spaced apart along the curved portions 21 with respect to the support members 23.

[0023] Next, a case in which the flatness of the glass plate G is measured will be described.

[0024] (Configuration Step)

[0025] First, the curved portions 21 of the support members 23 disposed at intervals from each other on the base 27 are placed and disposed with both side edge portions Ga of the glass plate G as a measurement object. Thus, the glass plate G is supported by the support members 23. Then, the glass plate G is deformed along the curved portions 21 of the support members 23, and is curved in an arc shape protruding upward (a side in which the stylus 13 is in contact).

[0026] Next, clamping members 25 are assembled from the side of the support member 23. This clamps hold the two side edges Ga of the glass plate G between the retaining pieces 33 of the clamping members 25 and the curved portion 21 of the support member 23. Thus, the glass plate G is maintained in a curved, upwardly convex arc shape along the curved portion 21.

[0027] (Measurement procedure)

[0028] After the glass plate G is placed on the clamping member 20, the stylus 13 of the probe 11 provided on the measuring device 10 is brought into contact with the surface of the middle portion of the glass plate G along the length direction of both side edges Ga. Then, by moving the probe 11, the stylus 13 is brought into contact with the upper surface of the glass plate G, while the glass plate G and the stylus 13 are moved in the bending direction Y of the glass plate G (refer to...). Figure 1 The measuring device 10 moves relative to the measuring direction X, which intersects with and is along the main surface of the glass plate G. The flatness is thus determined by measuring the unevenness of the surface shape of the glass plate G. It should be noted that the measuring direction X, which intersects with the bending direction Y of the glass plate G and is along the main surface of the glass plate G, is the direction that intersects with the two side edges Ga of the glass plate G, which are bent and supported by the clamping member 20. Furthermore, the measuring range for measuring flatness by contacting the stylus 13 in the glass plate G is defined as the portion other than the contact area between the support member 23 and the clamping member 25 and the holding piece 33. Additionally, the "flatness" in this application refers to the so-called "filtered centerline waviness curve." The "filtered centerline waviness curve" is a curve representing the surface waviness from which the surface roughness component has been removed. Specifically, it is obtained by removing the component corresponding to surface roughness (minor unevenness) from the cross-sectional curve that measures the surface shape using filtering (filtration processing) (SEMI D15-1296:2003).

[0029] However, the thin glass plate G may be damaged when bent excessively. On the other hand, if the bending amount is small, the reproducibility of the flatness measurement decreases, and the measurement accuracy may be reduced.

[0030] Therefore, the radius of curvature of the glass plate G bent when measuring the flatness of the glass plate G is preferably set to 50 mm or more and 500 mm or less. Bending the glass plate G with a radius of curvature of 50 mm or more can suppress damage caused by excessive bending of the glass plate G. Bending to 500 mm or less allows for good reproducibility and high accuracy in the measurement. It should be noted that the radius of curvature of the glass plate G bent when measuring the flatness of the glass plate G is more preferably 100 mm or more and 350 mm or less.

[0031] Here, the flatness of the glass plate G having a plate thickness of 0.2 mm was measured, and the reproducibility of the measurement results was evaluated. The flatness was measured by the measurement method of the first embodiment in which the glass plate G was set to the clamping member 20 and was bent in a convex upward manner, and a measurement method in which the glass plate G was set to the stage. Note that the radius of curvature of the glass plate G at the time of bending was set to 300 mm.

[0032] Figure 3 is a graph showing the flatness of the glass plate G measured by the measurement method of the first embodiment. Figure 4 is a graph showing the flatness of the glass plate G measured by setting the glass plate G to the stage. Note that in Figure 3 , the flatness of the glass plate G is shown when the flatness was measured three times while the glass plate G was set to the clamping member 20, and in Figure 4 , the flatness of the glass plate G is shown when the flatness of the glass plate G set to the stage was measured three times while the position on the stage was changed.

[0033] As shown in Figure 3 , in a case where the flatness was measured three times while the glass plate G was set to the clamping member 20 and was bent in a convex manner, the measurement results did not greatly deviate, and the flatness could be measured with high reproducibility. In contrast, as shown in Figure 4 , in a case where the flatness was measured three times while the glass plate G was set to the stage and the position on the stage was changed, the glass plate G was affected by the surface shape of the stage, and the measurement results deviated, and thus the flatness could not be measured with good reproducibility. As such, according to the measurement method of the flatness of the glass plate G of the present embodiment in which the flatness is measured while the glass plate G is bent in an arc shape in a convex manner, the glass plate G and the stylus 13 which contacts the surface of the glass plate G are relatively moved in a measurement direction X which intersects the bending direction Y and which is along the major surface of the glass plate G. Thus, compared to a method in which the flatness is measured by setting the glass plate G to the stage, the flatness of a thin glass plate G can be measured with high accuracy without being affected by the surface shape of the stage.

[0034] Thus, the flatness of a glass plate G, for example, having a thickness of 0.5 mm or less, preferably 0.3 mm or less, which is easily affected by the surface shape of the stage when set to the stage, can be measured with high accuracy. Note that the lower limit of the thickness of the glass plate G is not particularly limited, and is, for example, 0.1 mm.

[0035] Thus, the flatness of a glass plate G, for example, having a thickness of 0.5 mm or less, preferably 0.3 mm or less, which is easily affected by the surface shape of the stage when set to the stage, can be measured with high accuracy. Note that the lower limit of the thickness of the glass plate G is not particularly limited, and is, for example, 0.1 mm.

[0036] Further, by using the clamping member 20, the glass plate G can be easily bent into a convex arc shape suitable for measurement and arranged, and the flatness of the thin glass plate G can be smoothly measured.

[0037] (Second Embodiment)

[0038] Next, the second embodiment will be described. Further, the same reference numerals are assigned to the same structural parts as those of the first embodiment described above and the description thereof will be omitted.

[0039] Figure 5 is a schematic front view of a clamping member 40 provided with a glass plate G, which illustrates a method of measuring the second embodiment. Figure 6 is a VI-VI sectional view of Figure 5 Figure 7 is a VII-VII sectional view of Figure 6

[0040] As shown in Figure 5~Figure 7 , in the flatness measurement method of the glass plate G of the second embodiment, a clamping member 40 different from that of the first embodiment is used. This clamping member 40 is provided with a pair of support members 43 and a pair of locking members 47.

[0041] The support members 43 are formed in a plate shape or a block shape, and the upper portions thereof are formed into support portions 41 formed in a linear shape in the longitudinal direction. These support members 43 are arranged at intervals from each other on the upper surface of the base 27.

[0042] The locking members 47 are formed in a columnar shape, and have locking pins 45 at the side portions of the upper end portions. These locking members 47 are arranged at intervals from each other at the intermediate portions between the support members 43 on the base 27. These locking members 47 are erected on the base 27 in a state in which the locking pins 45 face each other.

[0043] Next, the case where the flatness of the glass plate G is measured will be described.

[0044] (Configuration Process)

[0045] First, on the base 27, the support portions 41 of the support members 43 arranged at intervals from each other support the both end edge portions Gb of the glass plate G as a measurement target, and the glass plate G is supported by the support members 43.

[0046] Next, while the locking pins 45 of the locking members 47 are locked to the both side edge portions Ga of the glass plate G, the locking members 47 are erected on the base 27. Thus, the both side edge portions Ga of the glass plate G are deformed by being lowered, and the glass plate G is bent into an arc shape in which the upper side (the side on which the stylus 13 contacts) is concave.

[0047] (Measurement Process) ​​

[0048] After the glass plate G is set to the clamping member 40, the stylus 13 provided to the probe 11 of the measuring device 10 is brought into contact with the surface of the middle portion of the glass plate G along the length direction of the both side edge portions Ga. Thereafter, by moving the probe 11, the glass plate G and the stylus 13 are relatively moved in the measurement direction X intersecting the bending direction Y of the glass plate G (refer to FIG. 1) and along the main surface of the glass plate G while the stylus 13 is in contact with the upper surface of the glass plate G. Thus, the flatness of the glass plate G is measured by the measuring device 10 by measuring the unevenness of the surface shape of the glass plate G. In the case of the present example, the measurement direction X intersecting the bending direction Y of the glass plate G and along the main surface of the glass plate G is a direction intersecting the both side edge portions Ga of the glass plate G bent and supported by the clamping member 40. Further, as the measurement range in which the flatness is measured by bringing the stylus 13 into contact with the glass plate G, the portion other than the contact portion of the clamping member 43 and the clamping member 47 with the clamping pin 45 is set. Figure 6

[0049] In the case of the flatness measurement method of the glass plate G of the second embodiment, as the radius of curvature of the glass plate G bent when the flatness of the glass plate G is measured, it is also preferable to be 50 mm or more and 500 mm or less. If the glass plate G is bent with a radius of curvature of 50 mm or more, damage due to excessive bending of the glass plate G can be suppressed. By bending with 500 mm or less, the measurement can be performed with good reproducibility and high accuracy. Note that, as the radius of curvature of the glass plate G bent when the flatness of the glass plate G is measured, it is more preferable to be 100 mm or more and 350 mm or less.

[0050] Thus, according to the flatness measurement method of the glass plate G of the second embodiment, the glass plate G and the stylus 13 in contact with the surface of the glass plate G are relatively moved in the measurement direction X intersecting the bending direction Y and along the main surface of the glass plate G in a state where the glass plate G is bent in an arc shape in a concave manner. Therefore, compared to a method in which the flatness is measured by setting the glass plate G on a platform, the flatness of a thin glass plate G can be measured with high accuracy without being affected by the surface shape of the platform.

[0051] Thus, the flatness of a glass plate G, for example, having a thickness of 0.5 mm or less, preferably 0.3 mm or less, which is easily affected by the surface shape of a platform when set on the platform, can be measured with high accuracy. Note that, the lower limit of the thickness of the glass plate G is not particularly limited, and is, for example, 0.1 mm.

[0052] Further, by using the clamping member 40, the glass plate G can be easily bent to be arranged in a concave arc shape suitable for measurement, and the flatness of a thin glass plate G can be smoothly measured.

[0053] ​Thus, the present application is not limited to the above-described embodiments, and various modifications, applications, and the like of the configurations of the embodiments based on the description and publicly-known technologies by those skilled in the art are also intended to be included in the scope of the present application.

[0054] As described above, the following matters are disclosed in the present specification.

[0055] (1) A flatness measuring method of a glass sheet, which measures flatness of a glass sheet, wherein the glass sheet is bent to be arranged in an arc shape that is convex or concave toward a stylus side of a measuring device, the stylus is brought into contact with a surface of the glass sheet, the glass sheet and the stylus are relatively moved in a direction that intersects with a bending direction of the glass sheet and that is along a main surface of the glass sheet.

[0056] According to the flatness measuring method of the glass sheet, the glass sheet and the stylus of the measuring device that is in contact with the surface of the glass sheet are relatively moved in the direction that intersects with the bending direction and that is along the main surface of the glass sheet in a state where the glass sheet is bent in the arc shape that is convex or concave, whereby the flatness of the glass sheet is measured. Thus, compared with a method in which the glass sheet is set on a platform to measure the flatness, the flatness of a particularly thin glass sheet can be measured with high accuracy without being affected by the surface shape of the platform.

[0057] (2) The flatness measuring method of the glass sheet according to (1), wherein the glass sheet is bent so that a radius of curvature becomes 50 mm or more and 500 mm or less.

[0058] According to the flatness measuring method of the glass sheet, damage due to excessive bending of the glass sheet can be suppressed, and the glass sheet can be moderately bent, and the flatness of a thin glass sheet can be measured with high reproducibility and high accuracy.

[0059] (3) The flatness measuring method of the glass sheet according to (1) or (2), wherein a thickness of the glass sheet is 0.5 mm or less.

[0060] According to the flatness measuring method of the glass sheet, the flatness of a glass sheet having a thickness of 0.5 mm or less that is easily affected by the surface shape of the platform when set on the platform can be measured with high accuracy.

[0061] (4) The flatness measuring method of the glass sheet according to any one of (1) to (3), wherein a pair of support members having a curved portion that protrudes in an arc shape are arranged apart at an interval, both side edge portions of the glass sheet are arranged at the curved portions of the support members to suspend the glass sheet on the support members, The two side edge portions of the glass plate are fixed to the curved portions of the support members by the clamping members, so that the glass plate is curved in a convex manner.

[0062] According to the glass plate flatness measurement method, the glass plate can be easily curved into a convex arc shape suitable for measurement, and the flatness of a thin glass plate can be smoothly measured.

[0063] (5) The glass plate flatness measurement method according to any one of (1) to (3), wherein The pair of support members having linear support portions are arranged apart at intervals, The two end edge portions of the glass plate are arranged on the support portions of the support members to suspend the glass plate on the support members, The locking members having locking pins are lowered so that the locking pins are locked to the two side edge portions of the glass plate, so that the glass plate is curved in a concave manner.

[0064] According to the glass plate flatness measurement method, the glass plate can be easily curved into a convex arc shape suitable for measurement, and the flatness of a thin glass plate can be smoothly measured.

[0065] This application is based on Japanese Patent Application No. 2024-124608 filed on July 31, 2024, the content of which is incorporated herein by reference.

Claims

1. A flatness measuring method of a glass sheet, the flatness of a glass sheet being measured, wherein the glass sheet is bent to be convex or concave in an arc shape toward a stylus side of a measuring device, the stylus is brought into contact with a surface of the glass sheet, the glass sheet and the stylus are relatively moved in a direction intersecting a bending direction of the glass sheet and along a direction of a main surface of the glass sheet.

2. The flatness measuring method of a glass sheet according to claim 1, wherein the glass sheet is bent in a manner that a radius of curvature becomes 50 mm or more and 500 mm or less.

3. The flatness measuring method of a glass sheet according to claim 1, wherein a thickness of the glass sheet is 0.5 mm or less.

4. The flatness measuring method of a glass sheet according to any one of claims 1 to 3, wherein a pair of support members having a curved portion protruding in an arc shape are disposed apart at intervals, both side edge portions of the glass sheet are disposed on the curved portions of the support members to suspend the glass sheet on the support members, both side edge portions of the glass sheet are fixed to the curved portions of the support members by a clamping member, and the glass sheet is bent in a convex manner.

5. The flatness measuring method of a glass sheet according to any one of claims 1 to 3, wherein a pair of support members having a straight support portion are disposed apart at intervals, both end edge portions of the glass sheet are disposed on the support portions of the support members to suspend the glass sheet on the support members, a locking pin of a locking member having the locking pin is locked to both side edge portions of the glass sheet and is lowered, and the glass sheet is bent in a concave manner. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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