TWI711590B - Method for manufacturing glass substrate and glass substrate manufacturing apparatus - Google Patents

Abstract

The subject of the present invention is to suppress the occurrence of damage in the regions on both sides of the width direction of the glass plate when the glass plate is conveyed. The manufacturing method of the glass substrate of the present invention has: a forming step, which uses an overflow down-draw method to shape molten glass to form a glass plate; and a transport step, wherein one side of the glass plate is sandwiched by at least a pair of transport rollers in the width direction In the side area, the above-mentioned glass plate is conveyed downward. In the forming step, inclined regions are formed in the regions on both sides, and in the inclined regions, the thickness of the glass plate is inclined in the width direction so that the thickness of the glass plate becomes thicker toward the outside in the width direction. In the conveying step, the position at which the conveying roller clamps the glass plate is adjusted to be within a region where the inclination of the thickness of the portion of the glass plate facing the conveying roller in the inclined region is smaller than an allowable value.

Description

Manufacturing method of glass substrate and glass substrate manufacturing device

The present invention relates to a method for manufacturing a glass substrate and a glass substrate manufacturing device.

A method of manufacturing sheet glass (glass plate) using the down-draw method is known. The sheet glass formed by the down-draw method has a central area in the width direction with a substantially constant plate thickness, and an end portion (edge portion) located outside the central area in the width direction and having a thicker plate thickness than the central area. The central area has a product area that becomes a product of the glass substrate. In the down-draw method, in order to stably convey the formed sheet glass in the downward direction, the boundary area between the center area and the end of the sheet glass is clamped by the conveying rollers and conveyed in the downward direction (Patent Document 1) . [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2013-212987

[The problem to be solved by the invention]

Since the thickness of the end portion of the sheet glass is thicker than the thickness of the central area, in the boundary area, the plate thickness gradually increases from the central area side to the end side, and the plate thickness of the sheet glass varies according to the position in the width direction. Therefore, when the boundary area is clamped by the conveying roller, the contact area between the sheet glass and the conveying roller becomes smaller, and the pressure of the sheet glass from the conveying roller is likely to become uneven. If it is partially clamped by the conveying roller with a high pressure, the sheet glass may be damaged. When cutting in the subsequent step, the sheet glass may be broken with the damage as a starting point.

Therefore, the object of the present invention is to provide a glass substrate manufacturing method and a glass substrate manufacturing apparatus that can suppress damage to both sides of the glass plate in the width direction when the glass plate is conveyed. [Technical means to solve the problem]

One aspect of the present invention is a method for manufacturing a glass substrate, which is characterized by having: A forming step, which uses an overflow down-draw method to shape the molten glass to form a glass sheet; and In the conveying step, one side uses at least a pair of conveying rollers to clamp the two sides of the glass plate in the width direction, and the other side conveys the glass plate downward; In the forming step, an inclined area is formed on the two side areas, and the inclined area is inclined such that the thickness of the glass plate becomes thicker toward the outside in the width direction, and In the conveying step, the position at which the conveying roller clamps the glass plate is adjusted to be in a region where the inclination of the thickness of the glass plate facing the conveying roller in the inclined region is smaller than an allowable value.

Preferably, in the forming step, before the glass sheet is clamped by the conveying roller, the two side regions of the glass sheet are clamped by a cooling roller arranged on the upstream side of the conveying direction of the conveying roller, And The position at which the conveying roller clamps the glass plate is adjusted to a position separated from the position of the glass plate clamped by the cooling roller by a predetermined interval or more in the width direction.

Preferably, it further has a control step of adjusting the position where the conveying roller clamps the glass plate, and In the above-mentioned control step, the position at which the conveying roller clamps the glass plate is adjusted to be in a region where the inclination of the thickness of the glass plate facing the conveying roller in the inclined region is smaller than an allowable value.

Preferably, it further has a measuring step of measuring the inclination of the thickness of the glass plate in the inclined region, and In the above control step, the position at which the transport roller clamps the glass plate is adjusted based on the measurement result of the thickness of the central region in the width direction of the glass plate and the inclination of the thickness.

Preferably, in the above control step, the position at which the transport roller clamps the glass plate is adjusted to a region where the inclination of the thickness becomes smaller.

Preferably, the position at which the conveying roller clamps the glass plate is adjusted to a position separated from both ends of the glass plate in the width direction toward the inner side in the width direction by a predetermined interval or more.

It is preferable that the position where the said conveyance roller clamps the said glass plate is adjusted so that the thickness of the part of the said glass plate which opposes the said conveyance roller becomes in the area|region where the thickness becomes less than an allowable thickness.

Preferably, in the above-mentioned conveying step, a plurality of conveying rollers arranged at intervals in the conveying direction hold the two side regions while conveying the glass plate downward, and The more the conveying roller is located on the downstream side of the conveying direction, the above allowable value is set to a smaller value.

Another aspect of the present invention is a glass substrate manufacturing device, which is characterized by having: A forming device that uses an overflow down-draw method to shape the molten glass to form a glass sheet; and A conveying device, one side of which uses at least a pair of conveying rollers to clamp the two sides of the glass plate in the width direction, and the other side conveys the glass plate downward; The forming device forms inclined areas on the two side areas, and the inclined areas are inclined such that the thickness of the glass plate becomes thicker toward the outside in the width direction, and The position at which the conveying roller clamps the glass plate is adjusted to be in a region where the inclination of the thickness of the glass plate facing the conveying roller in the inclined region is smaller than an allowable value. [Effects of Invention]

According to the present invention, when the glass plate is transported, it is possible to transport the glass plate while suppressing damage to both sides of the glass plate in the width direction.

Using the manufacturing method of the glass substrate of this embodiment, for example, a glass substrate for a TFT (thin-film transistor) display is manufactured. The glass plate is manufactured using the overflow down-draw method. Hereinafter, the manufacturing method of the glass substrate of this embodiment will be described with reference to the drawings.

(1) Outline of manufacturing method of glass substrate First, referring to FIGS. 1 and 2, a plurality of steps included in a method of manufacturing a glass substrate and a glass substrate manufacturing apparatus 100 used in the plurality of steps will be described. As shown in FIG. 1, the manufacturing method of a glass substrate mainly includes melting step S1, clarification step S2, shaping step S3, cooling step S4, and cutting step S5. In addition, the glass substrate manufacturing method has a grinding step, a polishing step, a cleaning step, an inspection step, a packing step, etc., and the plural glass substrates laminated in the packing step are transported to the supplier of the ordering party.

The melting step S1 is a step of melting glass raw materials. After the glass raw material is prepared so as to have a desired composition, as shown in FIG. 2, it is injected into the melting device 11 arranged upstream. The glass raw material contains a composition such as SiO ₂ , Al ₂ O ₃ , B ₂ O ₃ , CaO, SrO, and BaO. Specifically, a glass raw material having a strain point of 660°C or higher is used. The glass raw material is melted in the melting device 11 to become molten glass FG (refer to FIGS. 3 and 4). The melting temperature is adjusted according to the type of glass. In this embodiment, the glass raw material is melted at 1500°C to 1650°C. The molten glass FG is sent to the clarification device 12 through the upstream pipe 23.

The clarification step S2 is a step of removing bubbles in the molten glass FG. The molten glass FG after the bubbles are removed in the clarification device 12 is sent to the forming device 40 through the downstream pipe 24.

The forming step S3 is a step of forming molten glass FG into sheet glass (sheet glass) SG. Specifically, after the molten glass FG is continuously supplied to the molded body 41 (refer to FIGS. 3 and 4) included in the molding device 40, it overflows from the molded body 41. The overflowing molten glass FG flows down along the surface of the formed body 41. Then, molten glass FG merges with the lower end part 41a (refer FIG. 3 and FIG. 4) of the molded object 41, and is shape|molded into sheet glass SG. The sheet glass SG has a side part (also referred to as an edge part or an end part) SP (refer to FIG. 6) located at the end of a width direction, and the width direction center area|region CA (refer FIG. 6) sandwiched between the side parts. The thickness of the side part of the sheet glass SG is formed to be thicker than the thickness of the central area. In the forming step S3, an inclined area (boundary area) SA (refer to FIG. 6) is formed on both side areas R and L (see FIG. 4) in the width direction of the sheet glass SG, and the inclined area (boundary area) SA is a sheet The thickness of the material glass SG is inclined so that it becomes thicker toward the width direction outer side. That is, the sheet glass SG further has an inclined area between the central area and the side portions (area that becomes a boundary). The so-called slant means that the thickness of the sheet glass SG changes in the width direction of the sheet glass SG, that is, it has a gradient, and the so-called slanted area means an area where the thickness of the sheet glass SG is inclined in the width direction. The central area of the sheet glass SG is an area that has a fixed thickness and becomes a product of the glass substrate. The plate thickness of the central area of the sheet glass SG is formed into a thin plate of 0.7 mm or less, preferably 0.4 mm or less, for example. In addition, the width direction of the sheet glass SG is a direction orthogonal to the direction in which the sheet glass SG flows down (also referred to as the flow direction or the conveying direction) and the thickness direction of the sheet glass SG.

In the cooling step S4, the following pull-down rollers (conveying rollers) arranged along the conveying direction of the sheet glass SG are used to clamp the two sides of the width direction of the sheet glass SG, and the sheet glass SG is conveyed downward and cooled (Slow cooling) steps. That is, in the cooling step S4, a conveying step is performed in which the sheet glass SG is clamped and conveyed in the downward direction. The transport procedure will be described in detail below. The sheet glass SG is cooled to a temperature close to room temperature through the cooling step S4. Furthermore, the thickness (plate thickness) of the glass substrate, the amount of warpage of the glass substrate, and the amount of strain of the glass substrate are determined according to the cooling state in the cooling step S4.

The cutting step S5 is a step of cutting the sheet glass SG, which has a temperature close to room temperature, into a specific size. In the cutting step S5, specifically, the slow-cooled sheet glass SG is cut to separate the end and the boundary area from the central area, and the central area of the sheet glass SG is cut to a specific length, whereby This obtains a glass substrate. The cut glass substrate is further cut to a specific size to produce a glass substrate of the target size.

Next, referring to FIGS. 3 to 5, the configuration of the molding device 40 included in the glass substrate manufacturing device 100 will be described.

(2) The composition of the forming device 3 and 4 show the schematic configuration of the forming device 40. 3 is a cross-sectional view of the forming device 40. FIG. 4 is a side view of the forming device 40.

The forming device 40 has a passage through which the sheet glass SG passes and a space surrounding the passage. The space surrounding the passage includes an overflow chamber 20, a forming chamber 30 and a cooling chamber 80.

The overflow chamber 20 is a space where the molten glass FG sent from the clarification device 12 is formed into sheet glass SG. The molten glass FG flows down along the surface of the formed body 41, merges at the lower end 41a of the formed body 41, and is formed into sheet glass SG.

The forming chamber 30 is disposed below the overflow chamber 20 to adjust the thickness and warpage of the sheet glass SG. In the forming chamber 30, a part of the cooling step ST4 is performed. The temperature of the sheet glass SG gradually decreases downstream of the lower end 41a of the formed body 41.

The cooling chamber 80 is arranged below the overflow chamber 20 to adjust the space of the strain amount of the sheet glass SG. Specifically, in the cooling chamber 80, the sheet glass SG in the forming chamber 30 passes through the slow cooling point and the strain point and is cooled to a temperature near room temperature. Furthermore, the inside of the cooling chamber 80 is divided into a plurality of spaces by a plurality of heat insulating members 80b arranged at intervals along the conveying direction of the sheet glass SG.

The molding device 40 mainly includes a molded body 41, a partition member 50, a cooling roll 51, a cooling unit 60, pull-down rolls 81a to 81g, heaters 82a to 82g, and a cutting device 90. The molding device 40 further includes a control device 500 (see FIG. 5). The control device 500 controls the driving parts of the respective components included in the molding device 40.

Hereinafter, each configuration included in the molding device 40 will be described in detail.

(2-1) Formed body The formed body 41 is provided in the overflow chamber 20. The molded body 41 shapes the molten glass FG into sheet glass SG by overflowing the molten glass FG.

As shown in FIG. 3, the formed body 41 has a substantially pentagonal cross-sectional shape (like a wedge shape). The front end of the substantially pentagonal shape corresponds to the lower end 41 a of the molded body 41.

In addition, the molded body 41 has an inflow port 42 (see FIG. 4) at the first end in the longitudinal direction (the left-right direction in FIG. 4). The inflow port 42 is connected to the aforementioned downstream pipe 24, and the molten glass FG flowing out of the clarification device 12 flows into the molded body 41 from the inflow port 42. A groove 43 is formed in the molded body 41. The groove 43 extends in the length direction of the molded body 41. Specifically, the groove 43 extends from the first end to the second end opposite to the first end in the width direction of the sheet glass SG. The groove 43 is formed to be the deepest near the inflow port 42 and gradually becomes shallower as it approaches the second end. The molten glass FG flowing into the molded body 41 overflows from a pair of top portions 41 b and 41 b of the molded body 41 and flows down along a pair of side surfaces (surfaces) 41 c and 41 c of the molded body 41. Then, the molten glass FG merges with the lower end 41a of the molded body 41 to become sheet glass SG.

At this time, the liquidus temperature of the sheet glass SG at the lower end 41a of the molded body 41 is 1100°C or more, and the liquid phase viscosity is 2.5×10 ⁵ poise or more, more preferably, the liquidus temperature is 1160°C or more, and The liquid phase viscosity is 1.2×10 ⁵ poise or more. In addition, the viscosity of the side portion (edge portion, end portion) of the sheet glass SG at the lower end 41a of the molded body 41 did not reach 10 ^5.7 poise.

(2-2) Partition member The partition member 50 is a member that blocks heat transfer from the overflow chamber 20 to the forming chamber 30. The partition member 50 is arrange|positioned in the vicinity of the junction point of molten glass FG. Moreover, as shown in FIG. 3, the partition member 50 is arrange|positioned at the both sides of the thickness direction of the molten glass FG (sheet glass SG) which merges at a junction point. The partition member 50 is a heat insulating material. The partition member 50 blocks the heat movement from the upper side to the lower side of the partition member 50 by partitioning the upper environment and the lower environment of the confluence point of the molten glass FG.

(2-3) Cooling roll The cooling roll 51 is installed in the forming chamber 30. More specifically, the cooling roller 51 is arranged directly below the partition member 50. Moreover, the cooling roller 51 is arrange|positioned on the both sides of the thickness direction of sheet glass SG, and the width direction both sides of sheet glass SG. The cooling rollers 51 arranged on both sides of the thickness direction of the sheet glass SG operate in pairs. That is, the widthwise side regions R and L of the sheet glass SG are sandwiched by two pairs of cooling rollers 51, 51, ....

The cooling roller 51 is air-cooled by air and other gases passing through the air-cooling pipe inside. The cooling roller 51 is in contact with the side (edge, end) of the sheet glass SG, and rapidly cools both sides of the sheet glass SG including the side (edge, end) by heat conduction (quenching step). The viscosity of the side part of the sheet glass SG in contact with the cooling roller 51 is a specific value (specifically, 10 ^9.0 poise) or more.

The cooling roller 51 is rotationally driven by a cooling roller drive motor 390 (refer to FIG. 5). The cooling roller 51 cools the areas R and L on both sides of the sheet glass SG, and also has the function of pulling the sheet glass SG downward.

(2-4) Cooling unit The cooling unit 60 is a unit that is installed in the overflow chamber 20 and the forming chamber 30, and cools the sheet glass SG to the vicinity of the slow cooling point. The cooling unit 60 has a plurality of cooling elements 61-65. In FIG. 4, the cooling unit 60 is only shown in the forming chamber 30. The plurality of cooling elements 61 to 65 are arranged along the width direction of the sheet glass SG and the flow direction of the sheet glass SG. Specifically, the plurality of cooling elements 61 to 65 include central area cooling elements 61 to 63 and side cooling elements 64 and 65. The central area cooling elements 61 to 63 perform air cooling to cool the central area CA of the sheet glass SG. Here, the central area of the sheet glass SG refers to the central portion in the width direction of the sheet glass SG, and is the area including the effective width of the sheet glass SG and its vicinity. In other words, the central area of the sheet glass SG is the area located between the areas R and L on both sides of the sheet glass SG. The central area cooling elements 61 to 63 are arranged at positions opposite to the surface of the central area CA of the sheet glass SG along the flow direction. The units included in the central area cooling elements 61 to 63 can be independently controlled. In addition, the side cooling elements 64 and 65 perform water cooling to cool the side regions R and L of the sheet glass SG. The side cooling elements 64 and 65 are arranged at positions opposite to the surfaces of the two side regions R and L of the sheet glass SG along the flow direction. Each unit included in the side cooling elements 64, 65 can be independently controlled.

(2-5) Pull-down rollers (conveying rollers) Pull-down rollers 81a-81g are installed in the cooling chamber 80, and pull down the sheet glass SG passing through the forming chamber 30 in the flow direction of the sheet glass SG to perform the sheet glass SG Transport. The pull-down rollers 81a to 81g constitute a conveying device that conveys the sheet glass SG in the downward direction. The pull-down rollers 81a to 81g are arranged inside the cooling chamber 80 at intervals in the flow direction. In the example shown in FIGS. 3 and 4, the pull-down rollers 81a to 81g are arranged in each space partitioned by the heat insulating member 80b. Furthermore, the pull-down rollers 81a-81g are arrange|positioned in the area in the cooling chamber 80 where the temperature of the sheet glass SG becomes below a slow cooling point. The area where the temperature of the sheet glass SG becomes below the slow cooling point refers to the area where the temperature of the central area of the sheet glass SG becomes below the slow cooling point, which means that the sheet glass SG is cooled to around room temperature after the slow cooling point and the strain point The temperature is the area in the cooling chamber 80 along the flow direction. The slow cooling point is the temperature at which the viscosity becomes 10 ¹³ poise, where it is 715.0°C. In the example shown in FIGS. 3 and 4, the position where the temperature of the sheet glass SG becomes the slow cooling point is between the heat insulating member 80b located on the most upstream side in the conveying direction and the conveying direction of the pull-down roller 81a. The down rolls 81a to 81g are respectively arranged on both sides of the sheet glass SG in the thickness direction (refer to FIG. 3) and on both sides of the width direction of the sheet glass SG (refer to FIG. 4). Thereby, the pull-down rollers 81a to 81g are in contact with both sides of the sheet glass SG in the width direction of the sheet glass SG, and pull the sheet glass SG downward. The pull-down rollers 81a to 81g arranged on both sides of the thickness direction of the sheet glass SG operate in pairs, and the pair of pull-down rollers 81a, 81a, ... pull the sheet glass SG downward.

The pull-down rollers 81a to 81g are driven by a pull-down roller drive motor 391 (refer to FIG. 5). In addition, the pull-down rollers 81a to 81g respectively rotate in the direction in which the upstream portion approaches the sheet glass SG. The peripheral speed of the pull-down rollers 81a to 81g is greater the lower the pull-down roller is on the downstream side. That is, among the plurality of pull-down rollers 81a to 81g, the peripheral speed of the pull-down roller 81a is the smallest, and the peripheral speed of the pull-down roller 81g is the largest.

Furthermore, each of the pull-down rollers 81a to 81g is controlled in the plate thickness direction by the control device 500 based on the measurement result of the pressure sensor (not shown) that measures the pressure contact force between the rollers. Position control. Specifically, the relative position of the above-mentioned one roller with respect to the above-mentioned other roller is controlled in such a way that one of the rollers constituting each pair of the pull-down rollers 81a to 81g sandwiches the sheet glass SG with a fixed force against the other roller.

Since the pull-down rollers 81a-81g clamp the high-temperature sheet glass SG, in order to prevent deformation due to heat, for example, air cooling is performed by air cooling pipes penetrating the inside of the pull-down rollers 81a-81g. In the above-mentioned inclined region where the sheet glass SG is clamped by the pull-down rollers 81a to 81g, the temperature of the sheet glass SG decreases (the viscosity increases). Especially when the thickness of the central area of the sheet glass SG is to be formed into a thin plate of 0.7 mm or less, preferably 0.4 mm or less, the holding heat of the sheet glass SG is small, and the sheet glass SG is easily affected by the down roll The effect of 81a～81g. If the viscosity of the inclined region clamped by the pull-down rollers 81a-81g increases, a viscosity difference will occur with other regions adjacent to the inclined region, which may cause strain and the like. Therefore, by realizing a temperature distribution in which the temperature of the sheet glass SG becomes uniform in the width direction, strain is suppressed in the inclined region sandwiched by the pull-down rollers 81a to 81g and the region adjacent to the inclined region. In order to adjust the position (nip position) at which the pull-down rollers 81a to 81g clamp the sheet glass SG, the pull-down rollers 81a to 81g are configured to be movable in the width direction. The holding position of the down rolls 81a-81g is adjusted in advance before the manufacturing method of the glass substrate, but it can also be adjusted in the manufacturing method of the glass substrate as described below.

(2-6) Heater The heater 82 (82a-82g) is installed inside the cooling chamber 80 to adjust the temperature of the internal space of the cooling chamber 80. Specifically, a plurality of heaters 82a to 82g are arranged in the flow direction of sheet glass SG and the width direction of sheet glass SG. In the example shown in FIG. 3 and FIG. 4, seven heaters 82a-82g are arrange|positioned at intervals in the flow direction of sheet glass SG, and are arrange|positioned in each space partitioned by the heat insulating member 80b. The heaters arranged in each space are configured by arranging, for example, seven heater elements (not shown) in a row along the width direction of the sheet glass. The seven heater elements heat the central area CA of the sheet glass SG and the two side areas R and L of the sheet glass SG including the inclined area sandwiched by the pull-down rollers 81a to 81g. The heaters 82a to 82g are output controlled by the control device 500 described below. Thereby, the ambient temperature near the sheet glass SG passing through the inside of the cooling chamber 80 is controlled, and the temperature of the sheet glass SG is controlled. By this, the temperature of the sheet glass SG is cooled down in order along the conveyance direction. With this temperature control, the self-adhesive area of the sheet glass SG passes through the viscoelastic area to the elastic area. In the cooling chamber 80, the temperature of the sheet glass SG is cooled from the temperature near the slow cooling point to the temperature near the room temperature by the control of the heaters 82a-82g.

The output of the heater element is independently controlled by the control device 500 to adjust the ambient temperature near the sheet glass SG in a manner that realizes a pre-designed temperature distribution in the sheet glass SG.

A thermocouple 380 is provided near each heater 82a to 82g as a mechanism for detecting the ambient temperature, for example. Specifically, plural thermocouples 380 are arranged at intervals in the flow direction of sheet glass SG and the width direction of sheet glass SG. The thermocouple 380 detects the temperature of the central part C of the sheet glass SG and the temperature of the areas R and L on both sides of the sheet glass SG, respectively. The output of the heaters 82a-82g is controlled based on the ambient temperature detected by the thermocouple 380.

(2-7) Cutting device The cutting device 90 cuts the sheet glass SG cooled to a temperature near room temperature in the cooling chamber 80. Specifically, the cutting device 90 cuts along the scribe line formed in the sheet glass SG to separate the end portion and the boundary area, and cuts the central area of the sheet glass SG to a specific length, and further cuts it to a specific size . The cutting device 90 cuts the sheet glass SG at specific time intervals. Thereby, sheet glass SG becomes a plurality of glass plates. The cutting device 90 is driven by a cutting device drive motor 392 (refer to FIG. 5).

(2-8) Control device The control device 500 includes a CPU (Central Processing Unit, central processing unit), RAM (Random Access Memory), ROM (Read Only Memory), hard disk, etc. The glass substrate manufacturing device 100 Control of the various ministries. FIG. 5 is a block diagram showing an example of the configuration of the control device 500 in an embodiment.

Specifically, as shown in FIG. 5, the control device 500 receives signals from various sensors (e.g., thermocouple 380) or switches (e.g., main power switch 381) included in the glass substrate manufacturing apparatus 100, and performs a cooling unit 60. Control of heaters 82a to 82g, cooling roll drive motor 390, pull-down roll drive motor 391, cutting device drive motor 392, etc.

(Transfer procedure) Fig. 6 is a diagram illustrating the clamping position of the pull-down roller in the conveying step. Fig. 6 shows a cross section of a region R on one side in the width direction of the sheet glass SG. In the following description, among the pull-down rolls 81a to 81g, the pull-down roll 81a will be representatively focused on, but the pull-down rolls 81b to 81g also adjust the nip position in the same manner as the pull-down roll 81a. Furthermore, in FIG. 6, the clamping position of the cooling roller 51 is also shown.

As described above, in the forming step, the inclined area SA located at the boundary between the central area CA and the end SP is formed. The area including the inclined area SA and the end portion SP is shown in the figure. The shape when viewed in cross-section is bulbous, and the degree of inclination (gradient) of the thickness varies in the width direction. Specifically, as it travels from the central area CA side to the outside in the width direction, the inclination of the thickness becomes larger and then becomes smaller. The area closer to the outside in the width direction than the position where the inclination of the inclined area SA becomes 0 is the end SP.

The inclined area SA is an area whose thickness is inclined so that the thickness of the sheet glass SG becomes thicker toward the outside in the width direction, and has a thickness gradient in the width direction. In this inclined area SA, a thickness difference (deviation) occurs at the position (width direction area) of the sheet glass SG facing the pull-down roller 81a, and the sheet glass facing both ends in the width direction of the pull-down roller 81a There is a difference in thickness between positions A and B of SG. Therefore, in the inclined area SA, the contact area between the pull-down roller 81a and the sheet glass SG is small, and the pressure contact force received by the sheet glass SG from the pull-down roller 81a is likely to become uneven. As a result, the sheet glass SG is partially clamped by the pull-down roller 81a with a large pressing force. Since the sheet glass SG is cooled to a temperature below the slow cooling point in the cooling chamber 80, it becomes hard. Therefore, depending on the nip position of the pull-down roll 81a, damage may occur. If such a damage is located in the sheet glass SG, when it is cut in a downstream step, the damage may stretch and the sheet glass SG may break. In the present embodiment, the pull-down roller 81a clamps the sheet glass at the clamping position in the region where the thickness of the part of the sheet glass SG opposite to the pull-down roller 81a in the inclined area SA is adjusted to be less than the allowable value. SG. In the region where the inclination of the thickness of the part of the sheet glass SG facing the down roll 81a is smaller than the allowable value, the thickness of the sheet glass SG has a small slope, so the contact area between the down roll 81a and the sheet glass SG is Compared with the case where the nip position is located in the region above the allowable value, the unevenness of the pressure contact force received by the sheet glass SG from the pull-down roller 81a is alleviated. Therefore, it is possible to prevent the sheet glass SG from being partially clamped by the pull-down roller 81a with a large pressing force, and it is possible to prevent the sheet glass SG from being damaged. In addition, the inclination of thickness is as follows, for example, it is represented by the thickness difference of the part of sheet glass SG which opposes a pull-down roll. In addition, the nip position of the pull-down roller only needs to be at least partly located in the inclined area. This aspect also includes the aspect in which the outer end in the width direction of the down roll is located at the inner end in the width direction of the inclined region.

As described above, generally, as the inclined area SA progresses from the central area CA side to the outside in the width direction, the degree of the inclination of the thickness becomes larger. In other words, in the inclined area SA, the degree of inclination of the thickness of the sheet glass SG becomes smaller as it approaches the central area CA. Therefore, the more the nip position is located inside the inclined area SA in the width direction, the greater the degree of unevenness of the pressure contact force received by the sheet glass SG from the pull-down roller 81a is alleviated, and the effect of suppressing damage is higher. The allowable value is set so that the pull-down roller 81a clamps the sheet glass SG in such a region. Furthermore, the inclined area SA includes not only the area where the thickness of the sheet glass SG at the position A opposite to the widthwise inner end of the down roll 81a is greater than the thickness of the central area CA, but also includes the same thickness as the central area CA And the area where the thickness of the sheet glass SG at the position B opposite to the outer end in the width direction of the down roll 81a is greater than the thickness of the central area CA.

Specifically, the allowable value is a value determined based on the thickness of the central area CA such that the thickness difference (deviation) between the position A and the position B of the sheet glass SG becomes a specific value or less. For example, the width direction length of the pulling roller 81a is The value of the above thickness difference within the range is expressed. The reason why it is the value corresponding to the thickness of the central area CA is that the thickness difference in the inclined area SA largely depends on the thickness of the central area CA, even if it is the same as the different sheet glass SG The position in the width direction will also vary greatly according to the thickness of the central area CA. Furthermore, since the allowable difference in thickness between positions A and B depends on the width (length along the width direction) of the pull-down roll 81a, the allowable value can also be the value obtained by dividing the width of the pull-down roll 81a by the thickness difference. The value determined below the specific value replaces the value of the above thickness difference.

Here, as an example, FIG. 7 shows graphs showing the relationship between the thickness of the central area CA and the thickness of the sheet glass SG at positions A and B, respectively. In Fig. 7, the graph with circular plot points indicates the upper limit of the thickness of the ideal sheet glass SG at position A, and the graph with square plot points indicates the ideal sheet glass SG at position B The upper limit of the thickness. The upper limit refers to the height in the thickness direction of positions A and B based on the main surface of the central area CA. Using this relationship, for example, when manufacturing sheet glass SG with a thickness of 0.7 mm in the central area CA, the upper limit of the ideal thickness at position A is 30 μm and the upper limit of the ideal thickness at position B is 100 The difference of μm 70 μm is set as the allowable value of the thickness difference. That is, the nip position of the pull-down roller 81a is adjusted to be located at a position where the thickness difference becomes 70 μm or less in the inclined area SA. In the example shown in FIG. 6, it is adjusted so as to be located further inward in the width direction than the line PL indicating the allowable value. . By adjusting the clamping position in this way, the unevenness of the pressing force received by the sheet glass SG from the pull-down roller 81a is alleviated compared to the case where the sheet glass SG is clamped on the outside in the width direction from the line PL. The sheet glass SG can be prevented from being damaged. As long as the clamping position of the pull-down roller 81a is adjusted to at least the area where the thickness of the part of the sheet glass SG facing the pull-down roller 81a is less than the allowable value, there is no need to adjust the thickness of the part to be the above-mentioned position A and position B It is within the area below the upper limit of the ideal thickness (allowable thickness below), but as described below, the clamping position of the pull-down roller 81a is preferably adjusted so that the thickness of this part becomes the more ideal position A and B Within the area below the upper limit of thickness. In addition, the upper limit of the ideal thickness of position A and position B is 15 μm and 80 μm respectively when the thickness of the central area CA is 0.6 mm, and when the thickness of the central area CA is 0.5 mm , Respectively, are 5 μm and 60 μm. When the thickness of the central area CA is 0.4 mm, they are 1 μm and 40 μm respectively. When the thickness of the central area CA is 0.3 mm, they are less than 1 μm, 30 μm, when the thickness of the central area CA is 0.2 mm, it is less than 1 μm and 20 μm, and when the thickness of the central area CA is 0.1 mm, it is less than 1 μm and 15 μm, respectively. The relationship between the thickness of the central area CA and the thickness of the sheet glass SG at positions A and B as shown in Fig. 7 is based on the observation of the condition of damage when the inclined area SA of the sheet glass SG is actually clamped by the down roll , To find out the thickness of the inclined area SA without damage and make it. The positions A and B are determined according to the width direction length of the pull-down roller 81a. When the width direction length of the down roll 81a is illustrated, it is 30-150 mm, for example.

The adjustment of the clamping position of the pull-down roller 81a can be performed, for example, by the following method: in the inspection step, etc., the thickness distribution in the inclined area SA is determined by measurement, and the determined thickness distribution is satisfied as described above The clamping position is determined in the area of the allowable value set by the method, that is, the position in the area where the thickness of the sheet glass SG is less than the allowable value is determined, and the pull-down roller 81a is moved to the determined position. The measurement of thickness distribution will be described below.

The holding position of the pull-down roller 81a is preferably a position where the inclination of the thickness of the part of the sheet glass SG opposite to the pull-down roller 81a is smaller than the allowable value, and the position where the inclination of the thickness is the smallest . In the example shown in FIG. 6, the position where the inclination of the thickness is small is located on the side away from the inner side in the width direction from the line PL. When the position B is located at the inner end of the inclined area SA in the width direction, the inclination of the thickness is the smallest.

Furthermore, it is preferable that the nipping position of the pull-down roller 81a is a position in a region where the thickness of the portion of the sheet glass SG facing the pull-down roller 81a is less than the allowable value. In addition, at least the position A and the position B One is the position below the allowable thickness (the upper limit of the above-mentioned more ideal thickness). The reason is that in a region with a large thickness, for example, when the sheet glass SG is clamped by the cooling roller 51 and deformed, the degree of inclination varies, and there is a pressing force that the sheet glass SG receives from the pull-down roller 81a. Circumstances that have changed. For example, in the above example of manufacturing sheet glass SG with a thickness of 0.7 mm in the central area CA, it is preferable that the clamping position of the pull-down roller 81a is adjusted to meet the requirements of the pull-down roller 81a whose thickness at position A becomes 30 μm or less The position of the inner end in the width direction and the position where the thickness at the position B becomes at least one of the positions of the outer end in the width direction of the pull-down roll 81a of 100 μm or less. In addition, the clamping position of the pull-down roller 81a is preferably located on the inner side in the width direction than the clamping position of the cooling roller 51, so as to avoid the aforementioned change in the pressure contact force.

On the other hand, the nip position of the pull-down roller 81a is set so that the position B is located at the inner end in the width direction of the inclined area SA, or is set on the outer side in the width direction from this end. If the position B exceeds the width direction inner end of the inclined area SA and is located on the width direction inner side, the sheet glass SG cannot be applied to the width direction outside force, so the sheet glass SG slides between the pull-down roller 81a and the sheet The glass SG may be bent, and the sheet glass SG may have poor shape. In addition, if the position B exceeds the above-mentioned end excessively and is located inward in the width direction, the cutting position in the cutting step (the position where the scribe line S is formed) needs to be set to be more inward in the width direction than the position A. Therefore, the product area Will become smaller. Furthermore, as in the example shown in FIG. 6, the scribe line S is usually set slightly inside the width direction of the boundary between the central area CA and the inclined area SA.

It is preferable that the clamping position of the down roll 81a is adjusted to a position spaced from the position Q of the width direction inner end of the sheet glass SG clamped by the cooling roll 51 to the width direction inner side by a predetermined interval L1 or more. It exists on the surface of the sheet glass SG clamped by the cooling roller 51, and it is crimped to the cooling roller 51 to form irregularities. Therefore, if the clamping position is close to the position Q, the thickness of the sheet glass SG is inclined The degree of this is greatly changed, and therefore, the pressure contact force received by the sheet glass SG from the pull-down roller 81a may be unstable. Also, as described above, generally, the inclined area SA has an area in which the inclination of the thickness increases and then decreases as it goes from the central area CA to the outside in the width direction. Therefore, if the clamping position is close to the position Q, it may not be able to The force on the outside in the width direction sufficiently acts on the sheet glass SG, and the sheet glass SG may slide with respect to the pull-down roller 81a during transportation. For this reason, the interval L1 is preferably 50% or more of the distance between the cooling roller 51 and the boundary between the inclined area SA and the central area CA, for example, 20 mm or more. For the same reason, it is preferable that the nip position of the pull-down roller 81a is adjusted to a position separated from the end of the sheet glass SG in the width direction toward the inner side in the width direction by a predetermined interval L2 or more. The interval L2 is preferably a length of 80% or more of the length of the inclined area SA and the end SP, for example, 30 mm or more. Furthermore, in FIGS. 3 and 4, the cooling roll 51 and the pull-down rolls 81a to 81g are shown larger than those shown in FIG. In addition, in FIG. 3, the clamping position of the sheet glass SG of the cooling roll 51 and the down rolls 81a-81g is shown differently from FIG.

Preferably, the manufacturing method of the glass substrate further has a control step of adjusting the clamping position of the pull-down roller 81a. In the control step, the clamping position of the pull-down roller 81a is adjusted to be in the area where the thickness of the portion of the sheet glass SG facing the pull-down roller 81a in the inclined area SA is smaller than the allowable value. In the control step, specifically, the control device 500 controls a driving device (not shown) that moves the pull-down roller 81a in the width direction by adjusting the clamping position of the pull-down roller 81a. In the control step, for example, it is determined at a fixed time interval whether the clamping position of the pull-down roller 81a is located in the area where the inclination of the above thickness is less than the allowable value, and it is determined whether the clamping position is located in the area where the inclination of the above thickness is less than the allowable value. In this case, the operation is continued without changing the clamping position of the pull-down roller 81a, and when it is determined that the inclination of the above-mentioned thickness is not in the region where the inclination of the above-mentioned thickness is less than the allowable value, the control device 500 controls the driving device so that the clamping position is at the inclination of the above-mentioned thickness The widthwise position of the pull-down roller 81a is adjusted within the area less than the allowable value. According to the manufacturing method of the glass substrate, when the inclination of the thickness of the sheet glass SG changes during operation and the holding position of the pull-down roller 81a is outside the area where the inclination of the thickness is less than the allowable value, the holding position is adjusted by feedback , Adjusting the clamping position of the pull-down roller 81a to a region where the inclination of the thickness is less than the allowable value can alleviate the unevenness of the pressure contact force received by the sheet glass SG from the pull-down roller 81a, thereby preventing damage to the sheet glass SG.

It is preferable that the manufacturing method of a glass substrate further has the measuring step of measuring the thickness inclination of the sheet glass SG in the inclination area SA when it has the said control process. Specifically, the thickness inclination of the sheet glass SG can be obtained by establishing a correspondence relationship between the thickness of the sheet glass SG measured at a plurality of locations in the width direction in the inclined area SA and each thickness and width direction position. The thickness of the sheet glass SG at each width direction position is measured, for example, using a measuring device (not shown) such as a laser displacement meter. The measuring device is connected to the control device 500, and is configured to output to the control device 500 information on the thickness and width direction position measured at a fixed time interval. The control device 500 obtains the thickness inclination from the information of the thickness and the width direction position among the information sent from the measuring device, and uses the obtained thickness inclination and the thickness of the central area CA of the sheet glass SG to make the above determination. As the thickness of the central area CA, the control device 500 may use the thickness set in advance before the operation, or the thickness of the central area CA measured by the same measuring mechanism as the above-mentioned measuring device during operation. Furthermore, the control device 500 maintains information related to the allowable value corresponding to the thickness of the central area CA. In the manufacturing method of the glass substrate, by feedback adjustment of the clamping position based on the thickness of the central area CA, especially when the thickness of the central area CA changes inclination of the thickness, the sheet can be relaxed accurately The non-uniformity of the pressure contact force received by the material glass SG from the pull-down roller 81a.

The allowable value of the inclination of the thickness is preferably set for each of the pull-down rollers 81a to 81g. In this case, it is more preferable to set the allowable value to a smaller value for the pull-down roller located on the downstream side. In the sheet glass SG, the part located on the downstream side has a lower temperature and harder, so it is more likely to be damaged and cracks are likely to occur than the part located on the upstream side. However, as described above, if the lower the downstream side of the pull-down roller, the smaller the allowable value of the thickness inclination, the lower the downstream side of the pull-down roller, adjust the nip position to the smaller the thickness of the inclination As for the part of the sheet glass SG, the unevenness of the pressing force applied to the sheet glass SG is greatly alleviated. By setting an allowable value for each of the pull-down rollers 81a to 81g in this way and specifying its size, it is possible to suppress the occurrence of damage in the areas on both sides of the sheet glass SG throughout the entire conveying direction. Furthermore, the part of the sheet glass SG located on the upstream side has a higher temperature and softer. Therefore, even if the nip position of the pull-down roller is located at the part of the sheet glass SG with a large inclination of the plate thickness, it is located on the downstream side Compared with the part of sheet glass SG, it is not easy to be damaged.

According to the present embodiment, the pull-down roller 81a clamps the sheet glass SG at the clamping position in the region where the thickness of the part of the sheet glass SG opposite to the pull-down roller 81a is adjusted to be less than the allowable value. Compared with the case where the nip position is outside the region smaller than the allowable value, the unevenness of the pressure contact force received by the sheet glass SG from the pull-down roller 81a is alleviated. Therefore, it is possible to prevent the sheet glass SG from being partially clamped by the pull-down roller 81a with a large pressing force, and it is possible to prevent the sheet glass SG from being damaged.

As mentioned above, the manufacturing method of the glass substrate and the glass substrate manufacturing apparatus of this invention were demonstrated in detail, but the specific structure of this invention is not limited to the said embodiment, It can change in the range which does not deviate from the summary of invention.

11‧‧‧Melting device 12‧‧‧Clarification device 20‧‧‧Overflow Chamber 23‧‧‧Upstream pipeline 24‧‧‧Downstream pipeline 30‧‧‧Forming room 40‧‧‧Forming device 41‧‧‧Form 41a‧‧‧Lower end 41b‧‧‧Top 41c‧‧‧Side 42‧‧‧Inlet 43‧‧‧Slot 50‧‧‧Partition member 51‧‧‧Cooling Roll 60‧‧‧Cooling unit 61～65‧‧‧Cooling element 80‧‧‧Cooling room 80b‧‧‧Insulation component 81a～81g‧‧‧Down roller 82a～82g‧‧‧Heater 90‧‧‧Cutting device 100‧‧‧Glass substrate manufacturing equipment 380‧‧‧thermocouple 381‧‧‧Main power switch 390‧‧‧Cooling roller drive motor 391‧‧‧Down roller drive motor 392‧‧‧Cutting device drive motor 500‧‧‧Control device A‧‧‧Location B‧‧‧Location CA‧‧‧Central area FG‧‧‧Molten glass L1‧‧‧Interval L2‧‧‧Interval PL‧‧‧line Q‧‧‧Location R, L‧‧‧Both sides area S‧‧‧crossed SA‧‧‧Sloping area (boundary area) SG‧‧‧Sheet Glass SP‧‧‧End

Fig. 1 is a flow chart of the manufacturing method of the glass plate of this embodiment. Fig. 2 is a schematic diagram showing a glass plate manufacturing device used in a glass plate manufacturing method. Fig. 3 is a schematic diagram (cross-sectional view) showing the outline of the forming apparatus. Fig. 4 is a schematic diagram (side view) showing the outline of the forming apparatus. Figure 5 is a control block diagram of the control device. Fig. 6 is a diagram illustrating the clamping position of the conveying roller. Fig. 7 is a diagram showing the relationship between the thickness of the central area and the thickness of the glass plate at the clamping position.

51‧‧‧Cooling Roll

81a‧‧‧Down roller

A‧‧‧Location

B‧‧‧Location

CA‧‧‧Central area

L1‧‧‧Interval

L2‧‧‧Interval

PL‧‧‧line

Q‧‧‧Location

S‧‧‧crossed

SA‧‧‧Sloping area (boundary area)

SG‧‧‧Sheet Glass

SP‧‧‧End

Claims (9)

A method for manufacturing a glass substrate, comprising: a forming step, which uses an overflow down-draw method to shape molten glass to form a glass plate; and a conveying step, one side of which is clamped in the width direction of the glass plate by at least a pair of conveying rollers In the above-mentioned forming step, the above-mentioned two-side regions are formed with inclined regions, and in the above-mentioned inclined regions, the thickness of the glass plate is the thickness of the glass plate toward the outside in the width direction The method of thickening is inclined in the width direction, and the position where the glass plate is clamped by the conveying roller in the conveying step is adjusted so that the thickness of the part of the glass plate facing the conveying roller in the inclined region is less than the allowable inclination The above allowable value is such that the thickness difference of the glass plate between the two positions of the glass plate opposite to both ends in the width direction of the conveying roller respectively, or divide the thickness difference by When the value obtained by the width direction length of the conveying roller becomes less than a specific value, the value is determined based on the thickness of the center region in the width direction of the glass plate between the two side regions. The method of manufacturing a glass substrate according to claim 1, wherein in the forming step, before the glass plate is clamped by the conveying roller, the cooling roller disposed on the upstream side in the conveying direction than the conveying roller is clamped. The two side regions of the glass plate, and the position where the glass plate is clamped by the transport roller is adjusted to a position spaced apart from the position of the glass plate clamped by the cooling roller to the inner side in the width direction by a predetermined interval or more. The method for manufacturing a glass substrate according to claim 1 or 2, which further has a control step of adjusting the position where the conveying roller clamps the glass plate, and in the control step, adjusting the position of the conveying roller holding the glass plate The inclination of the thickness of the portion of the glass plate facing the conveying roller in the inclined region is less than the allowable value. The method for manufacturing a glass substrate according to claim 3, which further has an inclination measuring step of measuring the thickness of the portion of the glass plate in the inclined region, and in the control step, based on the center of the glass plate in the width direction The thickness of the area and the measurement result of the tilt of the thickness are adjusted to adjust the position where the transport roller clamps the glass plate. The method for manufacturing a glass substrate according to claim 3, wherein in the above-mentioned control step, the position where the above-mentioned conveying roller clamps the above-mentioned glass plate is adjusted to be within a region where the inclination of the above-mentioned thickness becomes smaller. The method for manufacturing a glass substrate according to claim 1 or 2, wherein the position at which the conveying roller clamps the glass plate is adjusted to a position separated from both ends in the width direction of the glass plate to the inner width direction by a predetermined interval or more. The method for manufacturing a glass substrate according to claim 1 or 2, wherein the position where the glass plate is clamped by the conveying roller is adjusted so that the thickness of the portion of the glass plate facing the conveying roller is within the allowable thickness. Such as the manufacturing method of the glass substrate of claim 1 or 2, wherein in the above-mentioned conveying step, one A plurality of conveying rollers arranged at intervals in the conveying direction nip the above-mentioned two-side areas, while conveying the glass plate in the downward direction, and the conveying roller located on the downstream side of the conveying direction, the allowable value is set as The smaller the value. A glass substrate manufacturing device, characterized by having: a forming device that uses an overflow down-draw method to shape molten glass to form a glass plate; and a conveying device, one side of which is clamped in the width direction of the glass plate by at least a pair of conveying rollers On both sides, the glass plate is conveyed downward on one side; the forming device forms an inclined area on the two side areas, and in the inclined area, the thickness of the glass plate is such that the thickness of the glass plate becomes thicker toward the outside in the width direction It is inclined in the width direction, and the position where the glass plate is clamped by the transport roller is adjusted to be within the area where the thickness of the portion of the glass plate facing the transport roller in the inclined area is less than the allowable value; the allowable value To obtain the difference in the thickness of the glass plate between the two positions of the glass plate facing the two ends of the conveying roller in the width direction, or dividing the thickness difference by the length of the conveying roller in the width direction The way in which the value becomes below a specific value is determined based on the thickness of the central area in the width direction of the glass plate between the two areas.

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