JP2023166753A - Glass plate manufacturing method, glass plate, and glass plate package - Google Patents

Abstract

To prevent a damage of a glass plate loaded on a pallet in an upright orientation.SOLUTION: A method of manufacturing a glass plate includes a cutting step S3 of removing an end part Ga of a glass plate G1 in a width direction with the glass plate G1 supported in an upright orientation. The cutting step S3 includes a scribing step, and a bending and dividing step. In the scribing step, a scribe line SL2 is formed so that a maximum depth of a median crack MC in a bottom part BP1 of the scribe line SL2 is shallower than that in an intermediate part MP1 or upper part UP1 of the scribe line SL2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a glass plate, a glass plate, and a glass plate package.

As is well known, in displays such as liquid crystal displays and organic EL displays, glass plates are used as glass substrates and cover glasses. BACKGROUND ART As a method for manufacturing a glass plate, a method using a down-draw method represented by an overflow down-draw method, a slot down-draw method, and a redraw method is widely adopted. An example of a method for manufacturing a glass plate using the overflow down-draw method is as shown below.

As disclosed in Patent Document 1, the method for manufacturing a glass plate includes a forming step of forming a glass ribbon, and a first cutting step (X cutting step) of cutting out a glass plate from the formed glass ribbon by scribe cutting. Implement.

In the molding process, molten glass is supplied to an overflow groove provided at the top of the wedge-shaped molded body and caused to overflow. The overflowing molten glass is allowed to flow down along the side surfaces of the molded body, and then fused and integrated at the lower end of the molded body. Thereby, a plate-shaped glass ribbon is formed. Thereafter, the formed glass ribbon is drawn downward while being held between both front and back sides by pairs of rollers arranged in a plurality of upper and lower stages. At both widthwise end portions of the glass ribbon obtained in this manner, ear portions each having a thickness larger than the widthwise central portion are formed.

The scribe cutting performed in the first cutting process forms a scribe line along the width direction on the main surface of the glass ribbon being conveyed downward, and curves the peripheral area of the scribe line to apply bending stress to the scribe line. The glass ribbon is cut along the Thereby, a rectangular glass plate is cut out from the glass ribbon.

Next, in the method for manufacturing a glass plate, as disclosed in Patent Document 2, a second cutting step (Y cutting) in which ears formed at both ends of the glass plate in the width direction are removed by scribe cutting process).

The scribe cutting performed in the second cutting step forms a scribe line along the vertical direction on the main surface on the widthwise end side of the glass plate held in the vertical position. Thereafter, the glass ribbon is cut along the scribe line by bending the area around the scribe line to apply bending stress. This scribe cutting is performed separately on one end side and the other end side in the width direction of the glass plate. As a result, a glass plate having no ears at both ends in the width direction is obtained.

Next, in the method for manufacturing a glass plate, as disclosed in Patent Document 3, a step of loading the glass plates from which the ears have been removed onto a pallet and packing them (packing step) is carried out. Through this packing process, a glass plate package is formed by packing a plurality of glass plates in a vertical position on a pallet. The glass plate package is transferred to the next process or stored until the next process is performed.

JP2017-202958A Japanese Patent Application Publication No. 2017-226549 Japanese Patent Application Publication No. 2020-75752

In the conventional glass plate manufacturing method as described above, the glass plate packed in the glass plate package has scribe marks left on both end faces in the width direction due to the formation of scribe lines. For this reason, for example, when the glass plate package is transported, there is a risk that cracks may occur from the scribe marks due to impact or excessive stress being applied to the glass plate. Such cracks are particularly likely to occur at the bottom of glass sheets that are stacked vertically on pallets.

The present invention has been made in view of the above circumstances, and its technical problem is to prevent damage to glass plates stacked vertically on a pallet.

The present invention is intended to solve the above-mentioned problems, and is a method for manufacturing a glass plate, comprising a cutting step of removing widthwise ends of the glass plate while the glass plate is supported in a vertical position. , the cutting step includes a scribing step of forming a scribe line including a median crack on the glass plate in the vertical direction using a scribe tool, and a bending stress is applied to the glass plate on which the scribe line is formed to break it. In the scribing step, the maximum depth of the median crack at the bottom of the scribe line is shallower than the maximum depth of the median crack at the top or middle part of the scribe line. It is characterized by forming scribe lines.

After the breaking process, scribe marks caused by the scribe line remain on the end face of the glass plate, and the scribe marks include a median crack. The deeper the maximum depth of the median crack in the lower part of the end face of the glass plate, the more likely it is that cracks will occur. In the present invention, as described above, by reducing the maximum depth of the median crack at the bottom of the scribe line, the maximum depth of the median crack at the bottom of the end face of the obtained glass plate can be made shallow. This makes it possible to prevent damage to the lower part of the glass plates loaded on the pallet in a vertical position.

In addition, by making the maximum depth of the median crack at the top or middle part of the scribe line deeper than the maximum depth of the median crack at the bottom of the scribe line, the median crack at the top or middle part of the scribe line can be removed in the breaking process. Since the crack develops from the starting point, the bending stress applied to the glass plate can be made as small as possible. Thereby, in the folding process, the amount of glass powder generated from the upper part or the middle part of the scribe line can be reduced as much as possible.

In the method for manufacturing a glass plate according to the present invention, the maximum depth of the median crack at the middle part of the scribe line may be shallower than the maximum depth of the median crack at the upper part of the scribe line.

According to this configuration, in the folding process, the crack can stably grow from the upper part of the scribe line toward the lower intermediate part and lower part. This makes it possible to prevent cutting defects from occurring during the cutting process. Furthermore, even if the glass plate is warped, it is possible to break the glass plate without causing cutting defects.

In the method for manufacturing a glass plate according to the present invention, the maximum depth of the median crack at the upper part of the scribe line may be shallower than the maximum depth of the median crack at the middle part of the scribe line.

According to this configuration, in the folding process, the crack can stably grow upward and downward from the middle part of the scribe line. Thereby, the glass plate can be folded with high accuracy. Furthermore, because the maximum depth of the median crack at the top of the scribe line becomes shallow, even if the top of the glass plate is held by a holding means such as a chuck when transporting the glass plate after the cutting process, This can prevent damage to the upper part.

The present invention is intended to solve the above problems, and is a glass plate package comprising rectangular glass plates and a pallet on which the glass plates are stacked in a vertical position, the glass plates having a width It has an end face extending in the vertical direction at the end of the direction, the end face is a folding surface having a scribe mark including a median crack, and the maximum depth of the median crack at the lower part of the end face is It is characterized by being shallower than the maximum depth of the median crack at the upper or middle portion of the end face.

The deeper the maximum depth of the median crack in the lower part of the end face of the glass plate, the more likely it is that cracks will occur. In the present invention, as described above, by reducing the maximum depth of the median crack at the lower part of the end face extending in the vertical direction, it is possible to prevent damage to the lower part of the glass plate loaded on a pallet in a vertical position. .

In the glass plate package according to the present invention, the maximum depth of the median crack at the intermediate portion of the end face may be shallower than the maximum depth of the median crack at the upper part of the end face.

In the glass plate package according to the present invention, the maximum depth of the median crack at the upper part of the end face may be shallower than the maximum depth of the median crack at the middle part of the end face.

According to this configuration, even when the upper part of the glass plate is held by a holding means such as a chuck when manufacturing the glass plate package, it is possible to prevent the upper part of the glass plate from being damaged by impact or the like.

The present invention is intended to solve the above-mentioned problems, and is a rectangular glass plate having an end face extending in the sheet drawing direction, the end face being a breaking surface having a scribe mark including a median crack. The maximum depth of the median crack at one end of the end face in the board drawing direction is shallower than the maximum depth of the median crack at the other end or intermediate part of the end face in the board drawing direction. shall be.

According to this configuration, the glass plates are loaded on the pallet so that one end of the end face where the maximum depth of the median crack is shallow is located at the bottom of the glass plate, thereby preventing damage to the lower part of the glass plate. It becomes possible to prevent this.

According to the present invention, it is possible to prevent damage to glass plates stacked vertically on a pallet.

It is a flowchart which shows the manufacturing method of a glass plate. It is a perspective view showing a part of manufacturing method of a glass plate. It is a side view which shows the second cutting process in the manufacturing method of a glass plate. It is a perspective view showing an example of a glass plate. 5 is a graph showing the relationship between the position of the scribe line and the depth of the median crack regarding the glass plate of FIG. 4. FIG. It is a perspective view showing other examples of a glass plate. 7 is a graph showing the relationship between the position of the scribe line and the depth of the median crack regarding the glass plate of FIG. 6. FIG. It is a perspective view showing other examples of a glass plate. 9 is a graph showing the relationship between the position of the scribe line and the depth of the median crack regarding the glass plate of FIG. 8. It is a perspective view showing a packing process in a manufacturing method of a glass plate. It is a perspective view of a glass plate package.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 1 to 11 show an embodiment of a glass plate, a method for manufacturing the same, and a glass plate package according to the present invention.

As shown in FIG. 1, the method for manufacturing a glass plate according to the present invention mainly includes a forming step S1, a first cutting step S2, a second cutting step S3, and a packing step S4.

The molding step S1 is a step of molding the glass ribbon GR from the molten glass GM. As shown in FIG. 2, in the molding step S1, molten glass GM is supplied to the overflow groove 1a at the top of the wedge-shaped molded body 1 and is caused to overflow. The overflowing molten glass GM is allowed to flow down along the side surfaces of the molded body 1, and then fused and integrated at the lower end of the molded body 1.

Thereby, a plate-shaped glass ribbon GR is formed. Thereafter, the formed glass ribbon GR is drawn downward while being held between both front and back sides by pairs of rollers (not shown) arranged in a plurality of upper and lower stages. A cooling roller pair is arranged at the top of the roller pairs arranged in a plurality of upper and lower stages. In this embodiment, the board drawing direction Y in the forming process S1 is set along the up-down direction.

The molded glass ribbon GR has a first main surface 2 and a second main surface 3. In this embodiment, a glass ribbon GR is illustrated in which the first main surface 2 is a non-guaranteed surface and the second main surface 3 is a guaranteed surface. Here, the guaranteed surface is the surface on which elements, etc. are formed in the glass plate finally obtained from the glass ribbon GR, and the surface properties are guaranteed, whereas the non-guaranteed surface is This is a surface whose surface properties do not need to be guaranteed to the extent of a surface.

At both ends Ga in the width direction of the glass ribbon GR, ear parts each having a thickness larger than the center part in the width direction are formed. The thickness of the central portion in the width direction of the glass ribbon GR is 1000 μm or less, preferably 700 μm or less, more preferably 500 μm or less, and the lower limit thereof is, for example, 50 μm or more.

The first cutting step S2 is a step of cutting out the first glass plate G1 by scribe cutting along the width direction X from the glass ribbon GR formed in the forming step S1. The first cutting step S2 includes a scribing step of forming a scribe line SL1 on the glass ribbon GR with a scribe tool, and a breaking step of applying bending stress to the glass ribbon GR with the scribe line SL1 formed thereon and breaking it. .

In the scribing process, the scribe wheel 4 as a scribe tool is pressed against the surface of the glass ribbon GR and moves from the position shown by the chain line to the position shown by the solid line, thereby forming a scribe wheel 4 on the first principal surface 2 of the glass ribbon GR in the width direction X. A scribe line SL1 is formed along the line.

At this time, the region where the scribe line SL1 is formed is supported by a support member (not shown) from the second main surface 3 side. A gripping mechanism 5 is disposed below the scribing wheel 4 and the support member, but the gripping mechanism 5 is not operated during the scribing process.

After the scribe line SL1 is formed, the scribe wheel 4 and the support member are retracted to the retracted position. In the illustrated example, the scribe line SL1 does not reach both ends of the glass ribbon GR in the width direction, but it may reach both ends.

Next, in the folding step, the grasping mechanism 5 that grasps the lower end of the glass ribbon GR is rotated in the direction of the arrow a with the folding member 6 supporting the region where the scribe line SL1 is formed from the second main surface 3 side. By moving, bending stress is applied to the scribe line SL1. Thereby, the glass ribbon GR can be broken along the scribe line SL1. By this scribe cutting by folding, a rectangular first glass plate G1 having ears at both ends Ga in the width direction is cut out.

The first glass plate G1 is transported by the transport device 7 to a position where the second cutting step S3 can be performed (transport step). The transport device 7 is configured to transport the first glass plate G1 while holding it in a vertical position. The conveyance device 7 has a holding part 7a that holds the upper part of the first glass plate G1.

The holding portion 7a is configured, for example, by a chuck that grips the first glass plate G1, but is not limited thereto, and may be configured by a holding means such as a suction pad. The holding portion 7a is configured to be movable in a predetermined direction using a guide rail or the like. The holding part 7a holds only the upper part of the first glass plate G1 and conveys the first glass plate G1 in a vertical position in a suspended state.

The second cutting step S3 is a step of cutting the width direction end portion Ga of the first glass plate G1. That is, in the second cutting step S3, while the first glass plate G1 is supported in a vertical position by the conveying device 7, both ends Ga in the width direction are removed by scribe cutting along the vertical direction, and the second glass plate G2 is removed. Cut out.

The second cutting step S3 includes a scribing step of forming a scribe line SL2 including a median crack MC on the first glass plate G1 using a scribe tool, and applying bending stress to the first glass plate G1 on which the scribe line SL2 has been formed. A folding step of folding and splitting is included.

In the scribing step, a part of the second main surface 3 of the first glass plate G1 is supported by two support members (not shown). In this state, the two scribe wheels 8 as scribe tools form scribe lines SL2 at predetermined positions (positions slightly inside in the width direction from the ears) on both ends Ga in the width direction of the first glass plate G1. .

The two scribe wheels 8 move from the position shown by the chain line to the position shown by the solid line while respectively pressing predetermined positions on both widthwise ends Ga of the first main surface 2 of the first glass plate G1. Thereby, two scribe lines SL2 are formed along the first main surface 2 of the first glass plate G1 in the vertical direction.

The scribe line SL2 is configured in a straight line along the vertical direction so as to correspond to the board drawing direction Y. The scribe line SL2 has a starting end SL2a and a terminal end SL2b. In the present embodiment, the starting end SL2a of the scribe line SL2 is located below the upper end of the first glass plate G1, but the starting end of the scribe line SL2 is located at the upper end of the first glass plate G1. SL2a may be set. The distance from the upper end surface of the first glass plate G1 to the starting end SL2a of the scribe line SL2 is, for example, 10 mm to 300 mm.

Although the terminal end SL2b of the scribe line SL2 is located above the lower end of the first glass plate G1, the terminal end SL2b of the scribe line SL2 may be set at the lower end of the first glass plate G1. Good too. The distance from the lower end surface of the first glass plate G1 to the terminal end SL2a of the scribe line SL2 is, for example, 10 mm to 300 mm. In this case, the two scribe lines SL2 may be formed simultaneously or separately over time. Further, the starting end SL2a and the terminal end SL2b of the scribe line SL2 may be vertically reversed.

Hereinafter, the upper part of the scribe line SL2 starts from the upper end of the scribe line SL2 (starting end SL2a), and ends at a position 25% below the upper end surface of the first glass plate G1, and is indicated by the symbol UP1. The lower part of the scribe line SL2 starts from the lower end of the scribe line SL2 (terminating end SL2b), and ends at a position 25% above the lower end surface of the first glass plate G1, and is indicated by the symbol BP1. Further, a portion between the upper portion UP1 and the lower portion BP1 of the scribe line SL2 is referred to as the intermediate portion of the scribe line SL2, and is indicated by the symbol MP1. Note that the position 25% below the top end surface is defined as the distance A from the top end surface, where A is the length from the top end surface to the bottom end surface of the first glass plate G1 multiplied by 0.25. means a position that is only below. Further, a position 25% above the bottom end surface means a position above the bottom end surface by the above distance A.

As shown in FIG. 3, the scribe line SL2 forms a plastic deformation layer PDL and a median crack MC in the first glass plate G1. The plastically deformed layer PDL is formed by pressing the first main surface 2 of the first glass plate G1 with the scribe wheel 8. The median crack MC is formed by integrally forming a first crack MCa called a rib mark and a second crack MCb formed at a deeper position than the first crack MCa. In this embodiment, the combined depth (D1+D2) of the depth D1 of the first crack MCa and the depth D1 of the second crack MCb is referred to as the "median crack depth."

In the scribing process according to the present embodiment, by adjusting the pressing force of the scribe wheel 8 against the first main surface 2 of the first glass plate G1, the scribe line SL2 is formed along the longitudinal direction (sheet drawing direction Y). Median cracks MC are formed with different depths.

As shown in FIG. 2, in the folding process, the first glass plate G1 is supported by two support members 9 on the second main surface 3 side, and the first glass plate G1 is cut along two scribe lines SL2. Break G1. In this case, portions of the first glass plate G1 that are slightly closer to the center in the width direction than the two scribe lines SL2 are supported by the support members 9, respectively. In this state, by pushing both ends Ga of the first glass plate G1 in the width direction from the first main surface 2 side toward the back side (second main surface 3 side) using a pushing member (not shown), the first glass plate G1 is Break G1.

By scribing and cutting the first glass plate G1 by breaking at two places, both ends Ga in the width direction including the ears of the first glass plate G1 are removed. Thereby, a second glass plate G2 having no ears is obtained. In this case, the scribe cutting at the two locations may be performed simultaneously or may be performed separately over time. The widthwise dimension of the second glass plate G2 obtained is, for example, 1500 mm or more, preferably 2000 mm or more, and more preferably 3000 mm or more. On the other hand, the upper limit can be, for example, 4000 mm or less. Further, the dimension of the second glass plate G2 in the drawing direction is, for example, 1300 mm or more, preferably 2000 mm or more, and more preferably 2500 mm or more. On the other hand, the upper limit can be, for example, 3600 mm or less.

The drawing direction of the second glass plate G2 can be determined, for example, by irradiating light from a light source (for example, a xenon light) while adjusting the angle of the second glass plate G2 in a dark room, and projecting the transmitted light onto a screen. , can be observed as a striped pattern. Therefore, even in the state of the second glass plate G2 after molding, the plate drawing direction Y during molding can be specified.

The second glass plate G2 has an upper end surface ESU, a lower end surface ESB, and a pair of side end surfaces ESS newly formed by removing both widthwise ends Ga of the first glass plate G1. The upper end surface ESU and the lower end surface ESB of the second glass plate G2 are elongated surfaces extending along the horizontal direction in the second glass plate G2 in the vertical position. The side end surface ESS of the second glass plate G2 is an elongated folded surface extending along the vertical direction corresponding to the plate drawing direction Y. A scribe mark including a median crack MC formed in the second cutting step S3 (scribe step) remains on this side end surface ESS.

Hereinafter, a portion of the side end surface ESS in a range of 25% downward from the upper end surface ESU of the second glass plate G2 (25% of the length from the upper end surface ESU to the lower end surface ESB) is part) and is indicated by the symbol UP2. Further, a portion of the side end surface ESS that extends up to 25% upward from the lower end surface ESB of the second glass plate G2 is referred to as a lower part (end portion) of the side end surface ESS, and is designated by the symbol BP2. Further, a portion between the upper portion UP2 and the lower portion BP2 of the side end surface ESS is referred to as an intermediate portion of the side end surface ESS, and is designated by the symbol MP2.

The depth of the median crack MC of the scribe line SL2 formed on the first glass plate G1 in the second cutting step S3 corresponds to the depth of the median crack of the scribe mark remaining on the side end surface ESS of the second glass plate G2. . Therefore, by measuring the median crack depth (depth from the first principal surface 2) of the scribe marks remaining on the side end surface ESS of the second glass plate G2, the scribe line formed in the second cutting step S3 can be measured. The depth of the median crack MC related to SL2 can be specified. The depth of the median crack is measured, for example, by observing the side end surface ESS of the second glass plate G2 or the side end surfaces of both widthwise end portions Ga including the ears of the first glass plate G1 using an electron microscope. In the glass plate package and glass plate of the present invention, the maximum depth of the median crack at the upper, middle, and lower portions is a depth distribution obtained by measuring the depth of the median crack at a pitch of 100 mm along the plate drawing direction. shall be sought from. The depth of the median crack is measured by taking a sample including the side end surface ESS of the second glass plate G2 and using the sample to observe the side end surface ESS with an electron microscope.

Hereinafter, the relationship between the aspect of the median crack of the scribe mark remaining on the side end surface ESS of the second glass plate G2 and the median crack MC of the scribe line SL2 will be explained with reference to FIGS. 4 to 9.

FIGS. 4 to 9 illustrate a second glass plate G2 formed by scribe lines SL2 having different median cracks MC. In these examples, the median crack MC of the scribe mark SM remaining on the side end surface ESS of the second glass plate G2 is shown in FIGS. 4, 6, and 8.

In FIGS. 4, 6, and 8, the upper end SMa of the scribe mark SM corresponds to the starting end SL2a of the scribe line SL2. The lower end SMb of the scribe mark SM corresponds to the terminal end SL2b of the scribe line SL2.

Since the upper part of the scribe mark SM corresponds to the upper part of the scribe line SL2, the same reference numeral UP1 is used. Since the lower part of the scribe mark SM corresponds to the lower part of the scribe line SL2, the same reference numeral BP1 is used. Since the middle part of the scribe mark SM corresponds to the middle part of the scribe line SL2, the same reference numeral MP1 is used. The upper part UP1 of the scribe mark SM is included in the upper part UP2 of the side end surface ESS of the second glass plate G2. The lower part BP1 of the scribe mark SM is included in the lower part BP2 of the side end surface ESS, and the middle part MP1 of the scribe mark SM is included in the middle part MP2 of the side end face ESS.

FIG. 5 is a graph showing the relationship between the position of the scribe line SL2 in the sheet drawing direction Y for forming the second glass plate G2 illustrated in FIG. 4 and the depth of the median crack MC. 7 shows the relationship between the position of the scribe line SL2 and the depth of the median crack MC for forming the second glass plate G2 illustrated in FIG. 6, and FIG. 9 shows the relationship between the second glass plate G2 illustrated in FIG. 3 is a graph showing the relationship between the position of a scribe line SL2 for forming a median crack MC and the depth of a median crack MC. The position of the scribe line SL2 shown in FIGS. 5, 7, and 9 corresponds to the position of the scribe mark SM in the drawing direction Y on the side end surface ESS of the second glass plate G2.

As shown in FIG. 4, the depth of the median crack MC of the scribe mark remaining on the side end surface ESS of the second glass plate G2 of the first embodiment (depth from the first principal surface 2) is from the upper part UP1. It gradually decreases toward the lower part BP1. The depth of the median crack MC is the deepest at the upper end SMa of the scribe mark SM, and the shallowest at the lower end SMb of the scribe mark SM.

Therefore, the maximum depth of the median crack MC of the lower part BP2 (one end of the end surface ESS in the sheet drawing direction Y) in the side end surface ESS of the second glass plate G2 is the upper part UP2 (in the sheet drawing direction Y) of the side end surface ESS. It is shallower than the maximum depth of the median crack MC at the other end of the end surface ESS. Further, the maximum depth of the median crack MC at the lower part BP2 of the side end surface ESS is shallower than the maximum depth of the median crack MC at the intermediate portion MP2 of the side end surface ESS. Further, the maximum depth of the median crack MC at the intermediate portion MP2 of the side end surface ESS is shallower than the maximum depth of the median crack MC at the upper portion UP2 of the side end surface ESS.

In other words, as shown in FIG. 5, the depth of the median crack MC of the scribe line SL2 formed on the first glass plate G1 in the second cutting step S3 is the deepest (D _MAX ), the shallowest (D _MIN ) at the terminal end SL2b. Therefore, the scribe line SL2 is formed such that the maximum depth of the median crack MC in the lower part BP1 is also shallower than the maximum depth of the median crack MC in the upper part UP1. Further, the scribe line SL2 is formed such that the maximum depth of the median crack MC in the lower part BP1 is shallower than the maximum depth of the median crack MC in the middle part MP1. Further, the scribe line SL2 is formed such that the maximum depth of the median crack MC at the middle portion MP1 is shallower than the maximum depth of the median crack MC at the upper portion UP1.

In the example of the second glass plate G2 of the second embodiment shown in FIG. 6, the depth of the median crack MC of the scribe mark SM remaining on the side end surface ESS is the depth of the median crack MC of the scribe mark SM remaining on the side end surface ESS. It gradually increases downward from SMa. The depth of the median crack MC is maximum at the intermediate portion MP2 of the side end surface ESS. The depth of the median crack MC gradually decreases downward from the maximum position. The depth of the median crack MC is minimum at the lower end SMb of the scribe mark SM in the lower part BP2 of the side end surface ESS.

Therefore, in this example, the maximum depth of the median crack MC in the upper part UP2 of the side end surface ESS is shallower than the maximum depth of the median crack MC in the middle part MP2 of the side end surface ESS.

In other words, as shown in FIG. 7, the depth of the median crack MC of the scribe line SL2 formed on the first glass plate G1 in the second cutting step S3 is the deepest at the middle part MP1 (D _MAX ), and the depth at the end It becomes shallowest at part SL2b (D _MIN ). Further, the scribe line SL2 is formed such that the maximum depth of the median crack MC in the upper part UP1 is shallower than the maximum depth of the median crack MC in the middle part MP1.

In the modification of the second glass plate G2 of the first embodiment shown in FIG. 8, the depth of the median crack MC of the scribe mark SM remaining on the side end surface ESS is maximum at the upper end SMa of the scribe mark SM; It gradually decreases downward from the upper end SMa. The depth of the median crack MC gradually increases downward from the boundary position with the upper part UP2 of the side end surface ESS at the intermediate portion MP2 of the side end surface ESS, and reaches a maximum at the midway point. The maximum depth of the median crack MC at the middle portion MP2 of the side end surface ESS is shallower than the maximum depth of the median crack MC at the upper portion UP2 of the side end surface ESS. Note that the side end surface ESS may have maximum depth portions at multiple locations in the intermediate portion MP2. The depth of the median crack MC gradually decreases downward from the maximum position in the intermediate portion MP2. The depth of the median crack MC is minimum at the lower end SMb of the scribe mark SM in the lower part BP2 of the side end surface ESS.

In other words, as shown in FIG. 9, the depth of the median crack MC of the scribe line SL2 formed on the first glass plate G1 in the second cutting step S3 is maximum (D _MAX ) at the starting end SL2a, and It reaches a maximum (D _LM ) at MP1 and a minimum (D _MIN ) at the terminal end SL2b. The scribe line SL2 is formed such that the maximum depth _DLM in the intermediate portion MP1 is shallower than the maximum depth _DMAX of the upper portion UP1.

In the second glass plate G2 of the first and second embodiments, when the thickness is 200 μm or more, the maximum depth of the median crack MC at the lower part BP2 of the side end surface ESS can be, for example, 90 μm or less to prevent damage. From the viewpoint of this, the thickness is preferably 80 μm or less. On the other hand, from the viewpoint of stabilizing the folding, the minimum depth of the median crack MC in the lower part BP2 of the side end surface ESS is preferably 30 μm or more, more preferably 50 μm or more.

In the second glass plate G2 of the first embodiment, when the thickness is 200 μm or more, the maximum depth of the median crack MC at the upper part UP2 or middle part MP2 of the side end surface ESS is the maximum depth of the median crack MC at the lower part BP2 of the side end surface ESS. The maximum depth of the median crack MC in the upper part UP2 or the middle part MP2 of the side end surface ESS is 100 μm or more, from the viewpoint of minimizing the bending stress applied to the glass plate in the breaking process by making it deeper than the maximum depth. It is preferable that it is, and it is more preferable that it is 110 micrometers or more. On the other hand, the maximum depth of the median crack MC in the upper part UP2 or middle part MP2 of the side end surface ESS can be, for example, 180 μm or less.

In the second glass plate G2 of the second embodiment, when the thickness is 200 μm or more, the maximum depth of the median crack MC at the middle part MP2 of the side end surface ESS is determined by the breaking process at the lower part BP2 of the side end surface ESS. The maximum depth of the median crack MC in the middle part MP2 of the side end surface ESS is preferably 100 μm or more, from the viewpoint of minimizing the bending stress applied to the glass plate by making it deeper than the maximum depth of More preferably, it is 110 μm or more. On the other hand, the maximum depth of the median crack MC in the intermediate portion MP2 of the side end surface ESS can be, for example, 200 μm or less. From the viewpoint of preventing damage, the maximum depth of the median crack MC in the upper part UP2 of the side end surface ESS is preferably 90 μm or less, more preferably 80 μm or less. On the other hand, from the viewpoint of stabilizing the folding, the minimum depth of the median crack MC in the upper part UP2 of the side end surface ESS is preferably 30 μm or more, more preferably 50 μm or more.

The packing process S4 is a process of manufacturing a glass plate package by loading a plurality of second glass plates G2 on a pallet. The second glass plate G2 is transported to the pallet by the transport device 7 after the second cutting step S3 is completed.

As shown in FIG. 10, in the packing step S4, the second glass plate G2 cut out in the second cutting step S3 is stacked on the pallet 11 alternately with the protective sheet 10 while being suspended and supported in a vertical position. To go. The protective sheet 10 is a foamed resin sheet, but may also be a non-foamable resin sheet, interleaf paper, or the like.

The second glass plate G2 that is about to be loaded onto the pallet 11 is oriented along a vertical plane. On the other hand, the back support surface 12a of the back support portion 12 of the pallet 11 is an inclined surface that slopes rearward as it moves upward. The angle of inclination of the back support surface 12a with respect to the horizontal plane is, for example, 60° to 85°. Therefore, although the glass plate laminate 13 constituted by the second glass plate G2 and the protective sheet 10 loaded on the pallet 11 is in a vertical position, it is inclined to follow the back support surface 12a.

The second glass plate G2 is loaded onto the pallet 11 while being suspended and supported in a vertical position by the conveying device 7. In this case, the second glass plate G2 is loaded on the pallet 11 so that the second main surface 3 serving as a guarantee surface faces the back support surface 12a of the pallet 11.

As shown in FIG. 11, the glass plate package GPB manufactured by carrying out the packaging process S4 has a rectangular second glass plate G2 and a rectangular protective sheet 10 in a vertical position (strictly speaking, in the above-mentioned inclined position). ) and a pallet 11 on which the glass plate laminates 13 are loaded. Furthermore, the glass plate package GPB also includes packing tools such as a binding band Ba for preventing the glass plate laminate 13 from collapsing.

The pallet 11 includes a bottom support part 14 that supports the bottom surface of the glass plate laminate 13 in addition to the back support part 12 having the inclined back support surface 12a described above. The bottom receiving surface 14a of the bottom support portion 14 is an inclined surface that slopes upward as it moves toward the front side.

According to the present embodiment described above, in the second cutting step S3, the depth of the median crack MC at the lower part BP1 of the scribe line SL2 formed on the first glass plate G1 is set from the median crack MC at the upper part UP1 or the middle part MP1. The depth of the median crack MC of the scribe mark SM in the lower part BP2 of the side end surface ESS of the cut out second glass plate G2 can be made as shallow as possible. In the state of the glass plate package GPB, there is a risk that the lower part BP2 of the side end surface ESS may be damaged due to the load or impact acting on the second glass plate G2 during transportation. In particular, as the depth of the median crack MC of the scribe mark SM becomes deeper, the lower part BP2 of the side end surface ESS is more likely to be damaged. In this embodiment, by making the depth of the median crack MC of the scribe mark SM at the lower part BP2 of the side end surface ESS of the second glass plate G2 shallow, it is possible to prevent the lower part of the second glass plate G2 from being damaged. Become.

Furthermore, by making the depth of the median crack MC at the upper part UP1 or middle part MP1 of the scribe line SL2 in the second cutting process S3 deeper than the depth of the median crack MC at the lower part BP1 of the scribe line SL2, the second cutting process S3 In the folding step, it is possible to reduce the amount of glass powder generated from the upper portion UP1 or the intermediate portion MP1 as much as possible.

Note that the present invention is not limited to the configuration of the embodiment described above, nor is it limited to the effects described above. The present invention can be modified in various ways without departing from the gist of the invention.

In the above embodiment, an example was shown in which the depth of the median crack MC of the scribe mark SM on the broken surface (side end surface ESS) of the second glass plate G2 is measured, but the present invention is not limited to this configuration. For example, in the second cutting step S3, by measuring the depth of the median crack of the scribe mark remaining on the folding surface of the width direction end Ga cut from the first glass plate G1, the median crack at the scribe line SL2 is measured. The depth of the MC may also be measured.

8 Scribe wheel (scribe tool)
11 Pallet BP1 Lower part of the scribe line BP2 Lower part of the side end surface of the second glass plate ESS Side end face of the second glass plate G1 First glass plate G2 Second glass plate Ga Widthwise end of the first glass plate GPB Glass plate packaging Body MC Median crack MP1 Middle part of the scribe line MP2 Middle part of the side end surface of the second glass plate S3 Second cutting process SL2 Scribe line SM Scribing mark UP1 Upper part of the scribe line UP2 Upper part of the side end face of the second glass plate X Width direction Y board pulling direction

Claims (7)

A method for manufacturing a glass plate, comprising a cutting step of removing widthwise ends of the glass plate while the glass plate is supported in a vertical position,
The cutting process includes a scribing process in which a scribe line including a median crack is formed vertically on the glass plate using a scribe tool, and a folding process in which bending stress is applied to the glass plate on which the scribe line is formed to break it. including a splitting process;
In the scribing step, the scribe line is formed such that the maximum depth of the median crack at the bottom of the scribe line is shallower than the maximum depth of the median crack at the upper or middle part of the scribe line. Characteristic glass plate manufacturing method. The method for manufacturing a glass plate according to claim 1, wherein the maximum depth of the median crack at the middle part of the scribe line is shallower than the maximum depth of the median crack at the upper part of the scribe line. The method for manufacturing a glass plate according to claim 1, wherein the maximum depth of the median crack at the upper part of the scribe line is shallower than the maximum depth of the median crack at the middle part of the scribe line. A glass plate package comprising a rectangular glass plate and a pallet on which the glass plates are stacked in a vertical position,
The glass plate has an end face extending in the vertical direction at an end in the width direction,
The end surface is a broken surface having scribe marks including a median crack,
A glass plate package characterized in that the maximum depth of the median crack at the lower part of the end face is shallower than the maximum depth of the median crack at the upper or middle part of the end face. The glass plate package according to claim 4, wherein the maximum depth of the median crack at the intermediate portion of the end face is shallower than the maximum depth of the median crack at the upper part of the end face. The glass plate package according to claim 4, wherein the maximum depth of the median crack at the upper part of the end face is shallower than the maximum depth of the median crack at the middle part of the end face. A rectangular glass plate,
It has an end surface extending in the board drawing direction,
The end surface is a broken surface having a median crack,
The maximum depth of the median crack at one end of the end face in the board drawing direction is shallower than the maximum depth of the median crack at the other end or intermediate part of the end face in the board drawing direction. glass plate.

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