CN114585475A

CN114585475A - Method for producing glass plate and glass plate

Info

Publication number: CN114585475A
Application number: CN202080073551.4A
Authority: CN
Inventors: 太和田佑; 星野爱信; 松本直之
Original assignee: Nippon Electric Glass Co Ltd
Current assignee: Nippon Electric Glass Co Ltd
Priority date: 2019-12-23
Filing date: 2020-11-18
Publication date: 2022-06-03
Also published as: TW202126427A; JP7415267B2; KR20220113352A; JP2021098258A; WO2021131421A1

Abstract

The method for manufacturing a glass plate comprises a first processing step (S1) for processing the end (GE) of the glass plate (G) by a first grinding stone (1) and a second processing step (S2) for grinding the end (GE) of the glass plate (G) which has undergone the first processing step (S1) by a second grinding stone (2). In the second processing step (S2), the second grinding stone (2) is relatively moved in the longitudinal direction of the end (GE) of the glass sheet (G) and the second grinding stone (2) is relatively moved in the thickness direction of the glass sheet (G).

Description

Method for producing glass plate and glass plate

Technical Field

The present invention relates to a glass sheet and a method for producing the same.

Background

A glass plate is used for displays such as liquid crystal displays and organic EL displays. When there is damage to the end portion of the glass plate, cracks or the like are generated from the damage, and therefore, in order to prevent this, grinding or polishing is performed on the end portion of the glass plate.

For example, patent document 1 discloses a method for processing a glass plate, including: a grinding process for conveying the glass plate in a specified direction and simultaneously chamfering the end of the glass plate by using a grinding stone; and a grinding process step of performing grinding processing by a grinding stone on the end part of the chamfered glass plate.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-103320

Disclosure of Invention

Problems to be solved by the invention

For example, when a glass plate is used as a substrate for a display, in a process of manufacturing an electronic device on the substrate, an end portion of the glass plate may be pressed against a pin or a roller for positioning. In this case, if a flaw remains at the end of the glass plate, glass frit tends to be generated. If the glass frit adheres to the surface of the glass plate, a disconnection defect of the electronic device is caused. Therefore, further improvement in the surface properties of the end portions of the glass sheet is desired.

However, if the surface properties of the entire end portion of the glass plate are improved, the entire end portion becomes mirror-like, and when the end portion of the glass plate is photographed by a camera, it becomes difficult to detect the end portion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce generation of glass frit at an end portion of a glass plate and to enable detection by a camera.

Means for solving the problems

The present invention has been made to solve the above-described problems, and provides a method for manufacturing a glass plate having a surface and an end portion, wherein the end portion of the glass plate has an end surface and a connection surface formed between the end surface and the surface, the method for manufacturing a glass plate includes a first processing step of processing the end portion of the glass plate by a first grinding stone and a second processing step of grinding the end portion of the glass plate having undergone the first processing step by a second grinding stone, and in the second processing step, the second grinding stone is relatively moved in a longitudinal direction of the end portion of the glass plate and the second grinding stone is relatively moved in a thickness direction of the glass plate.

According to this configuration, in the second processing step, the second grindstone is moved relatively in the thickness direction of the glass plate while moving the second grindstone relative to the end portion of the glass plate in the longitudinal direction thereof, so that the end face is processed mainly, and the surface roughness of the end face becomes smaller than the surface roughness of the connection face. Since the positioning pins and rollers contact the end surfaces having a small surface roughness, the generation of glass powder can be reduced. In addition, when the end portion of the glass plate is photographed by the camera, the end face is mirror-shaped, but the connection surface is not mirror-shaped, and therefore the end portion can be detected based on the connection surface.

Here, when the entire end portion of the glass plate is polished, abrasive grains are easily melted by the processing heat, and the wear of the grindstone is increased or the surface properties are rather deteriorated. In the second processing step, since the end surface is mainly processed, the processing heat can be reduced to suppress the erosion of the abrasive grains. Therefore, the consumption of the grindstone can be reduced, and the surface properties of the end face can be further improved.

In the method for manufacturing a glass plate according to the present invention, the second grinding wheel may have a groove portion for grinding the end surface of the glass plate, the groove portion may have a bottom portion that is in contact with the end surface of the glass plate and a regulation surface that is continuous with the bottom portion and is contactable with the connection surface, the bottom portion of the groove portion may have a width larger than a thickness of the end surface of the glass plate, and the width of the bottom portion before the second processing step is performed may be smaller than a sum of the thickness of the end surface and a relative movement distance of the second grinding wheel in the thickness direction.

According to this configuration, by setting the width of the bottom portion of the groove portion of the second grindstone in the above range, the end face of the glass plate can be appropriately ground by the bottom portion of the groove portion while the second grindstone is relatively moved with respect to the glass plate, and the connection surface of the glass plate can be brought into contact with the regulation surface of the groove portion. Thus, when a plurality of glass plates are manufactured, the end portions can be stably processed.

In the method for manufacturing a glass plate according to the present invention, the second grindstone may have an outer peripheral surface on which no groove portion is formed before the second processing step is performed, and the end portion of the glass plate may be polished by the outer peripheral surface of the second grindstone in the second processing step.

When the groove portion is formed in the outer peripheral surface of the second grinding stone, only the groove portion can be used for processing in the outer peripheral surface, and the number of glass sheets that can be processed by a single second grinding stone is reduced. If the second grinding stone having the outer peripheral surface on which the groove portion is not formed is used, most of the outer peripheral surface can be used for processing, and the number of glass sheets that can be processed by the single second grinding stone can be greatly increased.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a glass plate having a surface and an end portion, wherein the end portion has an end surface and a connection surface formed between the end surface and the surface, and a surface roughness Ra1 of the end surface is smaller than a surface roughness Ra2 of the connection surface.

According to this structure, the strength of the end face of the glass plate can be improved, and the product quality can be improved. Further, since the positioning pin and the roller are in contact with the end face having a small surface roughness, generation of glass powder can be reduced. When the end portion of the glass plate is photographed by the camera, the end face is mirror-shaped, but the connection surface is non-mirror-shaped, so that the end portion can be detected based on the connection surface.

In the above glass plate, a ratio Ra1/Ra2 between the surface roughness Ra1 of the end face and the surface roughness Ra2 of the connection face may be 0.15 to 0.6. According to this configuration, since the difference in reflectance between the end surface and the connection surface is increased, it becomes easy to detect the end portion based on the connection surface when the end portion of the glass plate is photographed by the camera.

The surface roughness Ra1 of the end face may be 0.06 μm or less. According to this configuration, generation of glass dust caused by contact between the positioning pin and the roller can be reliably reduced.

Effects of the invention

According to the present invention, generation of glass frit is reduced for the end portion of the glass plate, and detection can be performed using a camera.

Drawings

Fig. 1 is a perspective view showing a method for manufacturing a glass plate according to a first embodiment.

Fig. 2 is a sectional view showing the first grindstone and the glass plate.

Fig. 3 is a sectional view showing a first processing step.

Fig. 4 is a sectional view showing the second grindstone and the glass plate.

Fig. 5 is a diagram showing a locus of movement of the second grinding stone.

Fig. 6 is a sectional view showing a second processing step.

Fig. 7 is a sectional view showing a second processing step.

Fig. 8 is a sectional view showing a second processing step.

Fig. 9 is a diagram showing another example of the trajectory of the movement of the second grinding stone.

Fig. 10 is a diagram showing another example of the trajectory of the movement of the second grinding stone.

Fig. 11 is a sectional view showing a second processing step.

Fig. 12 is a sectional view showing a second processing step.

Fig. 13 is a sectional view showing a method of manufacturing a glass plate according to a second embodiment.

Fig. 14 is a sectional view showing a second processing step.

Fig. 15 is a sectional view showing the second processing step.

Fig. 16 is a sectional view showing the second processing step.

Fig. 17 is a sectional view showing the second processing step.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 to 12 show a first embodiment of the method for producing a glass sheet according to the present invention.

In the following example, a case of manufacturing a glass plate G having a rectangular shape with four sides will be described, but the shape of the glass plate G is not limited to the present embodiment. The glass sheet G is formed by a known forming method such as a float method, an overflow down-draw method, or a slit down-draw method, and is cut into a predetermined size. The thickness T of the glass plate G is 0.2 to 10mm, and the size of the glass plate G is 200mm × 300mm to 3100mm × 3500mm, but the range is not limited thereto. The composition of the glass sheet G is preferably alkali-free glass or aluminosilicate glass. Here, the "alkali-free glass" means a glass substantially free of alkali components (alkali metal oxides), specifically, a glass having an alkali component weight ratio of 1000ppm or less. The weight ratio of the alkali component is preferably 500ppm or less, more preferably 300ppm or less.

As shown in fig. 1, the glass sheet G has a first surface GS1, a second surface GS2, and end portions GE corresponding to the respective sides. In the present embodiment, the case where the end portions GE of the two parallel sides of the four sides of the glass sheet G are processed is exemplified. Each end GE of the glass sheet G includes a processing start end GEa and a processing end GEb.

As shown in fig. 1, the method includes a first processing step S1 of processing the end GE of the glass sheet G with the first grinding stone 1 and a second processing step S2 of processing the end GE of the glass sheet G with the second grinding stone 2 after the first processing step S1. XYZ in the figure is an orthogonal coordinate system. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is a vertical direction (up-down direction).

In the first processing step S1 and the second processing step S2, the grinding

stones

1 and 2 and the glass sheet G are moved relative to each other, whereby each end GE of the glass sheet G is processed from the processing start end GEa to the processing end GEb along the longitudinal direction (X-axis direction) thereof. For example, the end GE of the glass sheet G can be processed by the

grindstones

1 and 2 by moving the glass sheet G in the conveyance direction GX 1. Alternatively, the end GE of the glass sheet G may be processed by moving the grinding

stones

1 and 2 in the predetermined direction GX 2.

The first grinding wheel 1 used in the first machining step S1 is composed of, for example, a pair of rotary grinding wheels. The first grinding wheel 1 is, for example, a grinding wheel for chamfering the end GE of the glass sheet G. As the first grindstone 1, for example, an electrodeposited grindstone in which diamond abrasive grains are reinforced with a metal electrodeposited binder, or a metal bonded grindstone in which abrasive grains are reinforced with a metal bond is preferably used.

The first grinding wheel 1 is configured to be movable in the horizontal direction (X-axis direction and Y-axis direction) and the vertical direction (Z-axis direction) by a moving mechanism. The first grinding stone 1 is rotated about its axial center RC1 by a drive mechanism such as an electric motor.

As shown in fig. 1 and 2, the first grinding stone 1 has first groove portions 3 for processing the end portions GE of the glass sheet G. The first groove portion 3 has a bottom portion 3a and inclined surfaces 3b formed on both sides of the bottom portion 3 a. In the present embodiment, the first grinding wheel 1 in which the first groove portions 3 are formed in one stage is exemplified, but the present invention is not limited to this configuration, and a plurality of first groove portions 3 may be formed in the first grinding wheel 1. Further, the first processing step S1 may be performed on each end GE of the glass sheet G by the plurality of first grinding stones 1.

As shown in fig. 2, the end GE of the glass sheet G supplied to the first processing step S1 is formed of an end face including a corner portion GC. In the first machining step S1, the corner portions GC of the end portions GE are removed by chamfering the first grinding stone 1.

Specifically, as shown in fig. 3, the first grinding wheel 1 grinds the end GE of the glass sheet G by the bottom portion 3a and the inclined surface 3 b. In this case, the corner GC of the end GE of the glass plate G is removed by the inclined surface 3 b. By performing the first processing step S1, the end GE of the glass sheet G includes the end face ES1 (top) ground by the bottom portion 3a of the first grinding wheel 1 and the connection face ES2 ground by the inclined surface 3b of the first grinding wheel 1.

The end surface ES1 is configured to be flat or curved in accordance with the shape of the bottom portion 3a of the first grinding wheel 1. The connection surface ES2 is a boundary portion formed between the end surface ES1 and the surfaces GS1 and GS2 of the glass sheet G. The connection surface ES2 is formed in a curved surface shape so as to connect the surfaces GS1 and GS2 of the glass sheet G to the end surface ES 1.

The second grinding wheel 2 used in the second processing step S2 is composed of, for example, a pair of rotary grinding wheels for grinding the end faces ES1 of the glass sheet G. As the second grinding stone 2, a resin bond grinding stone using a resin bonding material (resin bond) as a bonding material of the abrasive grains is preferably used.

As the resin binder, a thermosetting resin is preferably used. As a specific example, a phenol resin, an epoxy resin, a polyimide resin, a urethane resin, or the like can be used as the resin binder.

As the abrasive grains bonded to the second grinding stone 2, one kind of abrasive grains selected from diamond grains, alumina grains, silicon carbide grains, cubic boron nitride grains, metal oxide grains, metal carbide grains, metal nitride grains, and the like, or two or more kinds of abrasive grains mixed can be used. The abrasive grains have a particle size of #1000 to 3000, for example, but not limited to this range.

The second grinding wheel 2 is configured to be movable in the horizontal direction (X-axis direction, Y-axis direction) and the vertical direction (Z-axis direction) by a moving mechanism. The second grinding stone 2 is rotated about its axial center RC2 by a drive mechanism such as an electric motor.

As shown in fig. 4, the second grinding wheel 2 has second grooves 4 on the outer peripheral surface 2a thereof for grinding the end GE of the glass sheet G. The second groove 4 can receive substantially all of the end GE of the glass sheet G, and the width W1 of the second groove 4 is larger than the thickness T of the glass sheet G. The second groove portion 4 has a bottom portion 4a contacting the end face ES1 of the glass sheet G and a pair of regulating surfaces 4b formed continuously on both sides of the bottom portion 4 a. The second groove portions 4 may be configured to receive a part of the end portions GE of the glass sheets G (for example, the end faces ES1 and the connection faces ES2 on the end face ES1 side). In this case, the width dimension W1 of the second groove portion 4 is larger than the maximum thickness of the portion of the end portion GE that is received by the second groove portion 4.

The bottom portion 4a is formed into a curved surface shape or a flat surface shape so as to correspond to the end surface ES1 of the glass sheet G. The regulating surface 4b is formed into a curved surface shape so as to correspond to the connecting surface ES2 of the glass sheet G.

The width W2 of the bottom 4a is larger than the thickness T1 of the end face ES1 of the glass sheet G. The width W2 of the bottom 4a is preferably 1 to 2.5 times the thickness T1 of the end ES1 of the glass sheet G (T1. ltoreq. W2. ltoreq. 2.5T 1).

In the present embodiment, the second grinding wheel 2 in which the single-stage second groove portions 4 are formed is exemplified, but the present invention is not limited to this configuration, and a plurality of stages of the second groove portions 4 may be formed in the second grinding wheel 2. Further, the second processing step S2 may be performed on each end GE of the glass sheet G by the plurality of second grinding stones 2.

In the second processing step S2, the second grinding stone 2 is relatively moved in the longitudinal direction (X-axis direction) of the end GE from the processing start end GEa toward the processing end GEb of the glass sheet G, and the second grinding stone 2 is relatively moved in the thickness direction (Z-axis direction) of the glass sheet G.

Fig. 5 shows a movement locus of the second grinding stone 2 in the second machining step S2. The second grindstone 2 is relatively moved in the X-axis direction with respect to the glass sheet G from the processing start position XS to the processing end position XE through the first intermediate position XM1 and the second intermediate position XM 2. The processing start end portion GEa of the glass sheet G contacts the second groove portion 4 of the second grinding stone 2 at the processing start position XS. At the machining end position XE, the second grinding stone 2 reaches the machining end GEb of the glass sheet G.

The second grinding wheel 2 reciprocates in the Z-axis direction while moving from the machining start position XS to the machining end position XE in the X-axis direction. That is, the second grinding wheel 2 moves (rises) from the reference position R0 by a distance L1 in the Z-axis direction to reach the first position Z1. Thereafter, the reference position Z0 is returned by moving (descending) the same distance L1, and then the reference position Z0 is moved (descended) by a distance L2 to reach the second position Z2.

In the present embodiment, the moving distance L1 from the reference position Z0 to the first position Z1 is equal to the distance L2 from the reference position Z0 to the second position Z2, but the present invention is not limited to this relationship.

In this case, the sum (L1+ L2) of the moving distances L1 and L2 from the reference position Z0 becomes the moving range of the second grinding stone 2 in the Z-axis direction. The width W1 of the second groove portion 4 of the second grinding stone 2 before (initially) performing the second processing step S2 is preferably smaller than the sum of the movement range (L1+ L2) and the thickness T of the glass sheet G (W1 < (L1+ L2+ T)). In addition, the width W2 of the bottom portion 4a of the second groove portion 4 before (initially) the second processing step S2 is preferably smaller than the sum of the moving range (L1+ L2) and the thickness T1 of the end face ES1 of the glass plate G (W2 < (L1+ L2+ T1)).

Next, a specific operation mode of the second grinding wheel 2 in the second machining step S2 will be described with reference to fig. 5 to 8.

As shown in fig. 5, the second grinding stone 2 is disposed at the machining start position XS at the reference position Z0 in the Z-axis direction.

As shown in fig. 6, when the processing start end portion GEa of the glass sheet G reaches the second grinding wheel 2, the center portion in the groove width direction (Z-axis direction) of the bottom portion 4a of the second groove portion 4 of the second grinding wheel 2 located at the reference position Z0 is in contact with the end face ES1 of the glass sheet G. In this case, the connection surface ES2 of the glass sheet G does not contact the restriction surface 4b of the second groove 4. That is, a gap is formed between the connection surface ES2 and the restriction surface 4b of the second groove portion 4.

While moving from the machining start position XS to the first intermediate position XM1 as shown in fig. 5, the second grinding wheel 2 is raised at a constant speed from the reference position Z0 in the Z-axis direction, and reaches the first position Z1. During this movement, only the end face ES1 of the glass sheet G is in contact with the bottom 4a of the second groove 4 in the second grinding wheel 2.

When the second grindstone 2 reaches the first position Z1, the connection face ES2 on the second surface GS2 side in the glass sheet G contacts the regulating face 4b on the lower side of the second groove portion 4 in the first position Z1 as shown in fig. 7. In this case, the connection surface ES2 presses the restriction surface 4b, and the glass sheet G elastically deforms in the Z-axis direction. Thereby, the connection surface ES2 on the second surface GS2 side of the glass sheet G is polished by the regulating surface 4b of the second groove portion 4.

Thereafter, the second grindstone 2 moves from the first position Z1 to the reference position Z0 at a constant speed in the Z-axis direction while moving from the first intermediate position XM1 to the second intermediate position XM 2. Further, the second grinding stone 2 moves from the reference position Z0 to the second position Z2 at a constant speed in the Z-axis direction while moving from the second intermediate position XM2 to the machining end position XE as shown in fig. 5.

While the second grinding wheel 2 is moving from the first position Z1 (the first intermediate position XM1) to the second position Z2 (the machining end position XE), the glass plate G is in a state in which only the end face ES1 is in contact with the bottom portions 4a of the second groove portions 4 in the second grinding wheel 2.

When the second grinding stone 2 reaches the second position Z2, the connection face ES2 on the first surface GS1 side in the glass plate G contacts the regulating face 4b on the upper side of the second groove portion 4 at the second position Z2 as shown in fig. 8. In this case, the connection surface ES2 presses the restriction surface 4b, and the glass sheet G elastically deforms in the Z-axis direction. Thereby, the connection surface ES2 on the first surface GS1 side of the glass sheet G is polished by the regulating surface 4b of the second groove portion 4.

Since the end surface ES1 is mainly machined in the second machining step S2, the surface roughness Ra1 (arithmetic mean roughness) of the end surface ES1 is smaller than the surface roughness Ra2 (arithmetic mean roughness) of the connection surface ES2 in the glass sheet G after the end of the second machining step S2. The ratio Ral/Ra2 of the surface roughness Ra1 of the end surface ES1 to the surface roughness Ra2 of the connecting surface ES2 is preferably 0.15 to 0.6. The surface roughness Ra1 of the end surface ES1 is preferably 0.03 to 0.06 μm. The surface roughness Ra2 of the connecting surface ES2 is preferably 0.1 to 0.2 μm.

In the present invention, the surface roughness Ral of the end face ES1 is measured at a plurality of locations (for example, the periphery of the machining start position XS, the periphery of the machining end position XE, and the periphery of the intermediate position thereof) at different positions in the longitudinal direction of the end face ES1, and the average value thereof is taken. The surface roughness Ra2 of the connection surface ES2 is measured at a plurality of positions at different positions in the longitudinal direction of the end surface ES1, and the maximum value of these is taken.

Fig. 9 and 10 show other examples of the movement locus of the second grinding wheel 2 in the second machining step S2.

In the example shown in fig. 9, the second grinding stone 2 passes through the fifth intermediate position XM5 from the first intermediate position XM1 during the movement from the machining start position XS to the machining end position XE.

While moving from the machining start position XS to the first intermediate position XM1, the second grinding wheel 2 does not move in the Z-axis direction (maintains the state of the reference position Z0), but moves relatively in the X-axis direction. The second grindstone 2 moves (rises) from the reference position Z0 to the first position Z1 in the Z-axis direction while moving from the first intermediate position XM1 to the second intermediate position XM 2. While the second grinding wheel 2 is moved from the processing start position XS to the second intermediate position XM2 via the first intermediate position XM1, only the end surface ES1 is ground by the bottom portions 4a of the second groove portions 4 in the glass sheet G.

While moving from the second intermediate position XM2 to the third intermediate position XM3, the second grinding stone 2 is relatively moved in the Z-axis direction along the X-axis direction while maintaining the first position Z1. During this movement, in the glass sheet G, the end face ES1 is polished by the bottom 4a of the second groove 4, and the connection face ES2 on the second surface GS2 side is polished by the lower regulation face 4b of the second groove 4.

While moving from the third intermediate position XM3 to the fourth intermediate position XM4, the second grindstone 2 moves from the first position Z1 to the reference position Z0 in the Z-axis direction. During this movement, the connection surface ES2 on the second surface GS2 side of the glass sheet G is separated from the restriction surface 4b of the second groove portion 4.

The second grindstone 2 moves from the reference position Z0 to the second position Z2 in the Z-axis direction while moving from the fourth intermediate position XM4 to the fifth intermediate position XM 5. While the second grinding stone 2 is moved from the third intermediate position XM3 to the fifth intermediate position XM5 via the fourth intermediate position XM4, only the end face ES1 is ground by the bottom portions 4a of the second groove portions 4 in the end portion GE of the glass plate G.

While moving from the fifth intermediate position XM5 to the machining end position XE, the second grinding wheel 2 is relatively moved in the Z-axis direction along the X-axis direction while maintaining the second position Z2. During this movement, in the glass sheet G, the end face ES1 is polished by the bottom 4a of the second groove 4, and the connection face ES2 on the first surface GS1 side is polished by the upper regulation face 4b of the second groove 4.

In the example shown in fig. 10, the second grinding wheel 2 passes through the eighth intermediate position XM8 from the first intermediate position XM1 while moving from the machining start position XS to the machining end position XE.

The second grinding stone 2 moves from the reference position Z0 to the second position Z2 in the Z-axis direction while moving from the machining start position XS to the first intermediate position XM 1. The second grindstone 2 moves from the second position Z2 to the reference position Z0 in the Z-axis direction while moving from the first intermediate position XM1 to the second intermediate position XM 2.

The second grindstone 2 moves from the reference position Z0 to the first position Z1 in the Z-axis direction while moving from the second intermediate position XM2 to the third intermediate position XM 3. The second grindstone 2 moves from the first position Z1 to the reference position Z0 in the Z-axis direction while moving from the third intermediate position XM3 to the fourth intermediate position XM 4. The second grinding stone 2 periodically repeats the same movement as described above while moving from the fourth intermediate position XM4 to the fifth intermediate position XM5, the sixth intermediate position XM6, the seventh intermediate position XM7, and the eighth intermediate position XM 8.

When the second processing step S2 described above is repeatedly performed on the plurality of glass sheets G, the second groove portions 4 of the second grinding stone 2 increase in depth due to the falling-off of the abrasive grains. Fig. 11 is a sectional view of the second grinding stone 2 in a case where the second machining process S2 has been performed a plurality of times. In this case, the depth D1 of the second groove 4 is deeper than the initial depth D0.

Fig. 12 is a cross-sectional view of the second grinding wheel 2 when the second machining step S2 is further performed a plurality of times by using the second groove portions 4 shown in fig. 11. In this case, the depth D2 of the second groove 4 is deeper than the depth D1 in fig. 11. As shown in fig. 12, the bottom portion 4a of the second groove portion 4 is gradually deformed from the initial curved surface shape to a larger curvature radius, that is, to a shape close to a flat surface, by repeating the second processing step S2.

As described above, in the second processing step S2, the second grinding stone 2 is relatively moved in the Z-axis direction so that the regulating surfaces 4b of the second groove portions 4 always contact the connecting surface ES2 of the glass sheet G. As described above, even when the second processing step S2 is repeatedly performed, the reduction in the width W2 of the bottom portion 4a can be suppressed, and the processing accuracy of the end face ES1 of the end portion GE can be maintained constant in each glass sheet G.

The glass plate thus manufactured is supplied to, for example, a manufacturing process of a display panel. In the process of manufacturing the electronic device with the first surface GS1, for example, the position of the end GE may be detected by imaging the end GE with a camera. In this case, the end surface ES1 and the connection surface ES2 having different surface roughnesses Ra1 and Ra2 are displayed in the captured image of the end portion GE. As described above, by performing the second processing step S2, the surface roughness Ra1 of the end face ES1 at the end portion GE of the glass plate is made smaller than the surface roughness Ra2 of the connection face ES 2. Thus, the end face ES1 and the connection face ES2 can be easily distinguished from each other in the captured image. Further, since the connection surface ES2 which is the boundary between the surfaces GS1 and GS2 of the glass sheet G and the end GE can be easily identified, the detection of the end GE in the image becomes easy.

In the process of manufacturing the electronic device with the first surface GS1, the positioning pins and rollers can be brought into contact with the end surface ES1 of the glass sheet G. Since the end surface ES1 has a small surface roughness Ra, generation of glass frit due to the contact can be reduced.

According to the method for manufacturing the glass sheet G of the present embodiment described above, the second processing step S2 polishes the end GE of the glass sheet G, thereby reducing the generation of glass powder in the end GE of the glass sheet G and facilitating the detection by the camera.

When the width W2 of the bottom 4a of the second groove 4 of the second grinding wheel 2 is made larger than the thickness T1 of the end face ES1 of the glass plate G, the positioning operation of the new second grinding wheel 2 can be performed efficiently at the time of the replacement operation of the second grinding wheel 2.

Fig. 13 to 17 show a second embodiment of the method for producing a glass plate of the present invention. In the present embodiment, the second processing step is different from the first embodiment.

As shown in fig. 13, the second groove portions 4 exemplified in the first embodiment are not formed in the outer peripheral surface 2a of the second grinding wheel 2 before (not used in) the second machining step S2.

As shown in fig. 14, in the first second processing step S2 in the present embodiment, when the first glass plate G1 comes into contact with the outer peripheral surface 2a, the second grinding stone 2 is moved relative to the glass plate G1 in the longitudinal direction (X-axis direction) of the end GE from the processing start end GEa to the processing end GEb and in the Z-axis direction (thickness direction of the first glass plate G1) as in the first embodiment. As shown in fig. 15, the second groove portion 4 having the width W3 and the depth D3 is formed in the second grinding wheel 2 in the first and second processing steps S2.

The depth D3 of the second groove 4 is smaller than the initial depth D0 of the second groove 4 in the first embodiment. That is, the second groove portion 4 of the first embodiment has a function of regulating the end GE of the glass sheet G by the regulating surface 4b when the glass sheet G is processed, but the second groove portion 4 of the present embodiment does not have this function.

When the second processing step S2 is performed, as shown in fig. 15, the second grinding stone 2 is disposed such that one end (upper end) in the groove width direction (Z-axis direction) of the second groove portion 4 overlaps the end face ES1 of the second glass plate G2. In this case, the end face ES1 of the second glass plate G2 contacts the outer peripheral surface 2a of the second grinding stone 2 where the second groove portions 4 are not formed.

Thereafter, the second grindstone 2 is moved relatively in the Z-axis direction as shown in fig. 16 while being moved relatively in the longitudinal direction (X-axis direction) of the end GE from the processing start end GEa toward the processing end GEb of the second glass plate G2, as in the case of processing the first glass plate G1. The second groove portion 4 formed by processing the first glass plate G1 is widened by processing the second glass plate G2. As shown in fig. 17, the width W4 of the second groove portions 4 after the second glass plate G2 is processed is larger than the width W3 of the second groove portions 4 immediately after the first glass plate G1 is processed. In this case, the depth D3 of the second groove portion 4 is substantially the same as the depth after the first second processing step S2.

In the third second processing step S2, the second grinding stone 2 is disposed so as to overlap one end portion in the groove width direction (Z-axis direction) of the second groove portion 4 after the second glass sheet G2 is processed (see fig. 17). In this case, the end face ES1 of the third glass sheet G3 is in contact with the outer peripheral surface 2a of the second grindstone 2 in which the second groove portions 4 are not formed.

Thereafter, the second grinding wheel 2 is moved relatively in the thickness direction (Z-axis direction) of the glass plate G3, and the end face ES1 is ground, as in the case of processing the second glass plate G2. Accordingly, in the second grinding wheel 2 of the present embodiment, the width of the second groove portion 4 is first widened by repeating the second processing step S2. When the second groove portions 4 spread over the entire outer peripheral surface 2a of the second grinding wheel 2, the second grinding wheel 2 is arranged at the same position as in the first second processing step S2, and the depth of a part of the second groove portions 4 is increased. Next, the second machining step S2 is repeated while changing the position of the second grinding stone 2 so that all the second grooves 4 have the same depth.

The method for producing the glass sheets G1 to G3 according to the present embodiment has the following advantages as compared with the first embodiment. When the second groove portions 4 are formed in the outer peripheral surface 2a of the second grinding stone 2 as in the first embodiment, only the second groove portions 4 are available for machining in the outer peripheral surface 2a, and the number of glass sheets G that can be machined by a single second grinding stone 2 is reduced. On the other hand, if the second grinding stone 2 having the outer peripheral surface 2a on which the second groove portions 4 are not formed is used as in the present embodiment, most of the outer peripheral surface 2a can be used for processing, and the number of glass sheets G that can be processed by a single second grinding stone 2 can be greatly increased.

The present invention is not limited to the configurations of the above embodiments, and is not limited to the above-described operational effects. The present invention can be variously modified within a scope not departing from the gist of the present invention.

In the above-described embodiment, the first processing step S1 and the second processing step S2 are performed on the two side end portions GE of the rectangular glass sheet G, but the present invention can also be applied to the remaining two side end portions GE.

The relative movement of the second grinding stone 2 in the Z-axis direction in the second processing step S2 may be performed by moving the glass sheet G in the Z-axis direction (thickness direction).

Description of the reference numerals

1 first grindstone

2 second grindstone

4 second groove part

End face of ES1

ES2 connecting surface

G glass plate

End of GE glass plate

GS1 first surface

GS2 second surface

S1 first working procedure

S2 second working procedure.

Claims

1. A method of manufacturing a glass sheet, the glass sheet having a surface and an end,

the method for manufacturing a glass sheet is characterized in that,

the end portion of the glass plate has an end face and a connection face formed between the end face and the surface,

the method for manufacturing a glass plate includes a first processing step of processing the end portion of the glass plate by a first grinding wheel and a second processing step of grinding the end portion of the glass plate having undergone the first processing step by a second grinding wheel,

in the second processing step, the second grinding wheel is relatively moved in the thickness direction of the glass plate while the second grinding wheel is relatively moved in the longitudinal direction of the end portion of the glass plate.

2. The method for producing glass sheet according to claim 1,

the second grindstone has a groove portion for grinding the end face of the glass plate,

the groove portion has a bottom portion that contacts the end surface of the glass plate and a restriction surface that is continuous with the bottom portion and is contactable with the connection surface,

the bottom of the groove portion has a width larger than a thickness of the end face of the glass plate,

the width of the bottom portion before the second working process is performed is smaller than the sum of the thickness of the end face and a relative movement distance of the second grinding stone in the thickness direction.

3. The method for producing glass sheet according to claim 1,

before the second processing step, the second grinding stone has an outer peripheral surface on which no groove portion is formed,

in the second processing step, the end portion of the glass plate is polished by the outer peripheral surface of the second grindstone.

4. A glass sheet having a surface and an end,

the glass sheet is characterized in that it is,

the end portion has an end face and a connection face formed between the end face and the surface,

the surface roughness Ra1 of the end face is smaller than the surface roughness Ra2 of the connection face.

5. Glass sheet according to claim 4,

the ratio Ra1/Ra2 of the surface roughness Ra1 of the end face to the surface roughness Ra2 of the connecting face is 0.15-0.6.

6. Glass sheet according to claim 4 or 5,

the surface roughness Ra1 of the end face is 0.06 [ mu ] m or less.