JP2012001391A - Apparatus for manufacturing glass plate and method for manufacturing each of glass plate, glass material for press molding, optical element and thin sheet glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for manufacturing a glass plate with which inward creasing and the generation of a nonuniform woody texture pattern are prevented without causing fusion of glass to a casting mold, so that a high-quality glass plate with a uniform thickness and small warpage can stably be molded; a method for molding a glass plate; and methods for manufacturing a glass material for press molding and an optical element.SOLUTION: The apparatus for manufacturing a glass plate includes a casting mold having a pair of opposed side walls which define the width of a glass plate, and a bottom part having a surface (a top surface) which forms one of opposed two principal surfaces of a glass plate. The bottom part internally has at least two through-holes which are substantially perpendicular to the side walls and substantially parallel to the top surface, and the through-holes have openings in side faces of the bottom part connecting to the outer surfaces of the side walls. The apparatus includes a cooling medium supply pipe having at least one discharge port for discharging a cooling medium on the side face. The cooling medium supply pipe is disposed in such a way that it is put in and taken out of the through-holes and at least one discharge port is located in the through-hole. When the cooling medium supply pipe is disposed in the through-hole, a cooling medium discharged from the discharge port has such a size and/or shape that it can flow out of the opening to the outside of the through-hole.

Description

  The present invention relates to an apparatus for producing a glass plate, and a method for continuously forming a glass plate that requires a high degree of homogeneity from molten glass, such as optical glass, using the production apparatus, and a glass plate produced by the method. The present invention relates to a method for producing a glass material for press molding, an optical element, and a thin plate glass.

  In the technology of forming glass with a high degree of homogeneity, such as optical glass, and with a high liquidus temperature (easily crystallized) as compared with plate glass for building materials, it has conventionally flowed out of an orifice with a small cross-sectional area. A method for producing a glass plate having a large cross-sectional area by continuously casting the obtained glass into a fixed mold installed horizontally is known.

  Patent Document 1 discloses a glass forming method in which molten glass is continuously discharged from an outflow pipe and poured into a mold to form the glass, and the formed glass is drawn out from a drawer opening provided on the side of the mold. Has been. In Patent Documents 2, 3, and 4, when the glass is formed by continuously flowing out the molten glass from the outflow pipe and pouring it into the mold, the glass is cooled by pressing the cooling plate against the upper surface of the softened glass in the mold. By doing so, it is described that a glass plate having a uniform thickness is obtained. The drawn glass plate is processed into a glass material for press molding an optical element such as a lens after annealing.

  In the column of the prior art of Patent Document 1, “In the molding technique using a fixed weir-groove mold provided directly under the glass outflow pipe, the upper surface of the mold directly under the outflow pipe is always taken from the continuously flowing molten glass. When heated, it becomes the highest temperature in the mold, and it becomes easy to fuse with glass. To prevent this fusion, the upper surface of the mold is controlled to be lower than other parts, and it is balanced. It is necessary to cool the mold with the device indicated as the cooler 3, 3 'and prevent the glass from fusing, as it is described. " Has been made.

Japanese Patent Publication No. 5-31505 JP 2002-265229 A JP 2004-292274 A JP 2009-46360 A

  In the mold described in Patent Document 1, a cooler 3 is arranged at a position directly below the outflow pipe and at a position downstream thereof in a direction orthogonal to the glass drawing direction, and the dam part and the side wall are cooled respectively. Containers 1 and 8 are arranged (FIGS. 1 to 2). Further, in the mold shown in FIGS. 5a and 5b, which is a conventional example in Patent Document 1, cooling is performed by disposing the cooler 1 directly below the outflow pipe and the weir part or the bottom part of the weir part. Promoting.

  When molding molten glass with the mold described in Patent Document 1, in order to prevent the glass from fusing to the mold, especially when the glass plate is molded while promoting cooling of the mold by the coolers 3 and 3 ′. When the width of the mold is relatively wide, and as a result, the width of the glass plate to be molded is relatively wide and the thickness of the glass plate to be molded is relatively thin (for example, the width is 100 mm or more and the thickness is 6 to In the range of 30 mm and width / thickness of 3-50, the flow rate of the molten glass flowing out from the orifice is relatively small (for example, 20-140 mL / min), and the thickness becomes uneven due to poor elongation. In some cases, the glass may be bent into the glass, or unevenness called a tree pattern may be unevenly formed on the bottom surface of the glass.

  On the other hand, when the flow rate of the molten glass flowing out from the orifice is relatively large (for example, more than 140 mL / min), the region of the high-temperature molten glass moves while expanding the width in the forming direction. If cooling is performed uniformly in the width direction and in an appropriate state in the vicinity of the orifice, the center line region in the downstream area is slightly cooled and may be fused to the mold. In addition, when the wide area is uniformly cooled, overcooling occurs near the off-center side wall, resulting in uneven thickness due to poor stretch, folding into the glass, and uneven surface irregularities. And cracks may occur. Moreover, if only the center line region is cooled so as not to be fused to the mold, warpage of the left and right objects occurs in the width direction.

  The portion where the folding occurs is not suitable for a material for an optical element because optical homogeneity is impaired. If the glass material for press molding made from a glass plate is not made using glass of a predetermined amount (constant weight) one by one, the molding accuracy at the time of press molding will decrease. If the thickness and width of the glass plate are constant, the glass plate can be divided into equal intervals in the shape of a bowl to obtain glass pieces of equal weight called cut pieces. Many glass materials can be made. However, if there is a non-uniform tree pattern on the upper surface of the glass plate, the plate thickness will vary, and even if the glass plate is divided at equal intervals, an equal weight cut piece or glass material cannot be obtained. Moreover, the same result is obtained even when the thickness of the glass becomes uneven due to poor elongation or the glass shape is warped. Therefore, the upper surface of the glass plate must be processed flat. Optical glass uses a large amount of expensive transition metal components such as rare earth components to increase the refractive index and expensive fluoride raw materials for low dispersion, but it is expensive by scraping the glass plate surface extensively. The problem is that glass is not used at all and becomes waste.

  As described above, even when the same mold is used, the viscosity of the molten glass flowing out from the orifice varies depending on the type of glass to be molded and the required size of the glass plate, and therefore the flow rate of the molten glass also changes. As a result, since the same mold is used, the width is the same, but the thickness and the moving speed of the glass to be molded in the mold are different. When the conventional mold described in Patent Document 1 is used, it has been difficult to mold a glass plate under optimum cooling conditions according to such changes in molding conditions.

  Therefore, the present invention solves the above problems, cools the glass to be molded under optimum cooling conditions according to the molding conditions of the glass plate, and folds the glass without fusing it to the mold. An object of the present invention is to provide a glass plate manufacturing apparatus that can stably form a high-quality glass plate that prevents the occurrence of denim and has a good shape, that is, a uniform thickness and a small warpage. Furthermore, the present invention uses the above-described manufacturing apparatus to prevent the glass from fusing to the mold, prevent the folding and the generation of non-uniform tree patterns, and stably form a high-quality glass plate having a good shape. It is an object of the present invention to provide a method and a method for producing a glass material for press molding and an optical element using a glass plate produced by this method.

  As a result of various studies to solve the above problems, the present inventors have provided at least one discharge port for discharging a cooling medium on the side surface in at least two through holes provided in the bottom of the mold. According to the glass plate manufacturing apparatus having a structure in which the cooling medium supply pipe can be inserted freely, the glass to be formed is cooled under optimum cooling conditions according to the molding conditions of the glass plate, and the glass is formed in the mold. The present invention has been completed by finding that a high-quality glass plate can be stably formed by preventing the occurrence of folding and non-uniform dendrites without fusing.

The present invention is as follows.
[1]
Production of a glass plate including a mold having a pair of opposing side walls defining the width of the glass plate and a bottom portion having a surface (hereinafter referred to as an upper surface) for molding one of the two opposing main surfaces of the glass plate A device,
The bottom portion has at least two through-holes therein, which are substantially orthogonal to the side wall and substantially parallel to the top surface, and the through-hole has an opening on a side surface of the bottom portion connected to the outer side surface of the side wall,
The manufacturing apparatus includes a cooling medium supply pipe having at least one discharge port for discharging a cooling medium on a side surface,
The cooling medium supply pipe is arranged so that it can be freely inserted into and removed from the through hole, and at least one of the discharge ports is located in the through hole;
When the cooling medium supply pipe is disposed in the through hole, the glass plate manufacturing apparatus has a size and / or shape that allows the cooling medium discharged from the discharge port to flow out of the through hole from the opening. .
[2]
Introducing a cooling medium into the cooling medium supply pipe disposed in the through hole, discharging the cooling medium from the discharge port, cooling the upper surface in the vicinity of the discharge port, It is used for forming the glass plate in the moving direction of the glass by continuously casting into the mold and moving the cast glass in one direction (hereinafter referred to as a forming direction) from the upstream side to the downstream side. The apparatus for producing a glass plate according to [1].
[3]
A plurality of the through holes and the cooling medium supply pipes are provided, and the plurality of cooling medium supply pipes have the same number of discharge ports or different numbers of discharge ports [1] or [2] The manufacturing apparatus of the glass plate of description.
[Four]
The plurality of cooling medium supply pipes have a different number of discharge ports, and the number of discharge ports increases in the forming direction [3].
[Five]
The cooling medium supply pipe has a gap through which the cooling medium discharged from the discharge port can flow out of the through hole between the side surface having the discharge port and the inner surface of the through hole facing the side surface. The apparatus for producing a glass plate according to any one of [1] to [4].
[6]
The number of the said through-hole and the said cooling-medium supply pipe | tube is a manufacturing apparatus in any one of [1]-[5] which is the range of 2-10.
[7]
The cooling medium supply pipe is a manufacturing apparatus according to any one of [1] to [6], wherein the cross-sectional shape is a semicircular shape, and the discharge port is provided in a semicircular flat portion.
[8]
[1] A method for producing a glass plate using the production apparatus according to any one of [7],
A step of preparing the manufacturing apparatus by determining the number and arrangement positions of the cooling medium supply pipes arranged in the manufacturing apparatus and the number of discharge ports of the cooling medium supply pipe;
In the mold of the prepared manufacturing apparatus, the molten glass flowing out from the orifice is continuously cast into the mold, and the glass cast along the both side walls is unidirectional from the upstream side to the downstream side (hereinafter, the molding direction). A step of continuously forming a flat glass plate while moving the glass plate, and the casting of the molten glass and the forming of the flat glass plate are performed when the upper surface of the orifice is viewed in plan view. Performing while locally cooling the area extending in the molding direction from the position directly below and the position immediately below the orifice (hereinafter referred to as cooling promotion area),
The manufacturing method of the glass plate characterized by the above-mentioned.
[9]
The number and arrangement positions of the cooling medium supply pipes arranged in the manufacturing apparatus, and the number of discharge ports provided in the cooling medium supply pipes are determined so that the cooling promotion region has substantially the same width in the molding direction. [8].
[Ten]
The number and position of the cooling medium supply pipes arranged in the manufacturing apparatus, and the number of discharge ports of the cooling medium supply pipes, the width of the cooling promotion region increases intermittently or continuously in the molding direction. [8] The production method according to [8].
[11]
In the manufacturing method of the glass material for press molding for heating, softening and press molding,
A glass plate is produced by the method according to any one of [8] to [10], the glass plate is divided to produce a plurality of glass cut pieces, and the glass piece for press molding that processes the cut pieces Production method.
[12]
In the method of manufacturing an optical element for producing a glass optical element through a process of heating, softening and press molding a glass material,
A method for producing an optical element, wherein a glass material for press molding is produced by the method according to [11], and the glass material is heated, softened, and press molded.
[13]
[8] A method for producing a thin glass, comprising producing a glass plate by the method according to any one of [10] and producing a thin glass from the glass plate through a process including slicing.

  According to the apparatus for producing a glass plate of the present invention, the glass to be formed is cooled under optimum cooling conditions according to the molding conditions of the glass plate, and the glass is not folded into the mold without being fused. It is possible to prevent the generation of uniform denim and stably form a high-quality glass plate.

It is the schematic which planarly viewed the casting_mold | template 1 which is an example of the casting_mold | template of the manufacturing apparatus of this invention. The vertical cross section in AA of FIG. 1 is shown. The cooling promotion area | region when the casting_mold | template shown in FIG. It is the schematic which planarly viewed the casting_mold | template 1 which is an example of the casting_mold | template of the manufacturing apparatus of this invention. The vertical cross section in AA of FIG. 4 is shown. The cooling promotion area | region when the casting_mold | template shown to FIG.

[Glass plate manufacturing equipment]
The glass plate manufacturing apparatus of the present invention includes a mold having a pair of opposing side walls that define the width of the glass plate and a bottom portion having a surface (upper surface) for molding one of the two opposing main surfaces of the glass plate. including. The bottom portion has at least two through-holes inside thereof that are substantially orthogonal to the side wall and substantially parallel to the top surface, and the through-hole has an opening on a side surface of the bottom portion that is connected to the outer side surface of the side wall. The manufacturing apparatus includes a cooling medium supply pipe having at least one discharge port for discharging a cooling medium on a side surface. The cooling medium supply pipe is disposed so as to be freely inserted into and removed from the through hole and so that at least one of the discharge ports is located in the through hole. When the cooling medium supply pipe is disposed in the through-hole, the cooling medium supply pipe has a size and / or shape that allows the cooling medium discharged from the discharge port to flow out of the through-hole from the opening.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 and 4 are schematic views in plan view of a mold 1 which is an example of a mold included in the manufacturing apparatus of the present invention. The mold 1 includes a pair of opposing side walls 11 and 11 ′ that define the width of the glass plate, and a bottom portion 13 having a surface (upper surface) that forms one of the two opposing main surfaces of the glass plate. The molten glass flowing out from the orifice 3 is continuously cast into the mold 1. A flat glass plate is continuously formed while moving the glass 2 cast along the both side walls 11 and 11 ′ in one direction (forming direction) from the upstream side to the downstream side. The glass 2 cast into the mold 1 is restricted to spread in the width direction by a pair of opposing side walls 11 and 11 ′, and is formed into a glass plate having a width equal to the interval between the pair of opposing side walls. By controlling the drawing speed of the glass plate and the flow rate of the molten glass flowing out from the orifice 3 so that the molten glass liquid level in the mold 1 is constant, a glass plate having a required thickness can be stably formed. Can do.

  The mold in the manufacturing apparatus of the present invention also has a stopper 12 corresponding to the weir part disclosed in Patent Document 1, and a glass plate molded in the molding direction as viewed from the stopper 12, that is, at a position facing the stopper 12. A mold opening (not shown) for drawing out is provided.

  2 illustrates a vertical section taken along line AA in FIG. 1, and FIG. 5 illustrates a vertical section taken along line AA in FIG. The upper surface of the bottom 13 of the mold 1 is a flat and smooth surface. The bottom 13 is provided with a plurality of holes 14 extending in the width direction substantially parallel to each other. Local cooling of the bottom is facilitated by locally cooling the desired location on the inner surface of each hole. Although the number of holes shown in the figure is 6, the number of holes can be appropriately set within a range of 2 to 10, for example. Also, if necessary, the number of holes can exceed ten.

  As described above, casting of molten glass and forming into a flat plate shape extend in the forming direction from the position immediately below the orifice 3 and the position immediately below the orifice 3 when the upper surface of the bottom portion 13 is viewed in plan. The cooling promotion region having substantially the same width is performed while locally cooling. Therefore, for cooling the bottom portion 13, a cooling medium supply pipe 4 (FIG. 1) having a flow path through which the cooling medium flows and having a discharge port 41 for discharging the cooling medium on the side surface, or the cooling medium on the side surface. The cooling medium supply pipe 5 (FIG. 4) having the discharge port 51 for discharging the water can be used. The cooling medium supply pipe 4 (5) is inserted into the hole 14 in the bottom portion 13 of the mold 1 so that the discharge port 41 (51) faces upward (in the direction of the upper surface of the bottom portion 13) (see FIGS. 2 and 5). When the cooling medium is caused to flow through the cooling medium supply pipe 4, the cooling medium is ejected from the discharge port 41 (51) and blown to the inner surface of the hole 14 facing the discharge port 41 (51). The inner surface of the hole 14 to which the cooling medium is blown faces the upper surface of the bottom portion 13, and only the portion where the discharge port 41 (51) is arranged is cooled, and the region including this portion becomes the cooling promotion region. However, strictly speaking, a region where the discharge ports in the bottom are distributed and a region where the cooling effect by the discharge of the cooling medium from the discharge port is caused by heat conduction correspond to the bottom cooling promotion region.

  A plurality of the through holes and the cooling medium supply pipes are provided as described above, and the plurality of cooling medium supply pipes may have the same number of discharge ports or different numbers of discharge ports.

  When a plurality of cooling medium supply pipes have the same number of discharge ports (the first embodiment), the cooling at each part where the cooling medium supply pipes are provided is set to the same condition. Can do. Further, when the plurality of cooling medium supply pipes have different numbers of discharge ports (second embodiment), the cooling at each part provided with the cooling medium supply pipes is performed according to the molding conditions. Cooling conditions can be set. When the plurality of cooling medium supply pipes have different numbers of discharge ports, the number of discharge ports can be increased in the molding direction. This point will be described later.

(First embodiment)
When the plurality of cooling medium supply pipes have the same number of discharge ports, as shown in FIG. 1, the shape, size, interval, and arrangement of the discharge ports 41 provided in each cooling medium supply pipe 4 And the number can be equal. By doing so, the cooling region can have substantially the same width toward the downstream. FIG. 1 shows, as an example, three cooling medium supply pipes 4 arranged in parallel so that the four discharge ports 41 face upward (in the direction of the upper surface of the bottom portion 13). 2 and 3 show a state in which three cooling medium supply pipes 4 are inserted into the three holes 14. The number of discharge ports 41 can be appropriately selected according to the cooling region. A plurality of cooling medium supply pipes 4 are inserted into the holes 14 of the mold bottom 13, and among the plurality of discharge openings provided in each cooling medium supply pipe, the central discharge opening coincides with the center in the mold width direction. Place each tube in The number and installation positions of the cooling medium supply pipes 4 can be appropriately determined in consideration of the size of the position of the cooling promotion region.

  As for the position of the cooling promotion region, if a position immediately below the orifice is a start position, a certain position from the position immediately below the orifice toward the molding direction is the final position. The final position is appropriately determined in consideration of the cooling state of the glass to be molded. Specifically, it is preferable that the position where the glass temperature is in the range of glass transition temperature Tg-100 ° C. to Tg + 100 ° C. is the final position. Further, until the lower surface temperature of the glass is cooled in the range of softening point to softening point −200 ° C., preferably in the range of softening point −30 ° C. to softening point −100 ° C., it is set so as to exist in the cooling promotion region. It is appropriate from the viewpoint of preventing the occurrence of non-uniform thickness and cracks in the glass surface, non-uniform unevenness and cracks on the glass surface due to poor stretch and poor elongation. . The thickness shape is determined based on the softening point, whereas the warped shape is determined based on the Tg standard. When the wall thickness is relatively large, warp is unlikely to occur because the strength of the sheet glass increases, and conversely, a temperature difference (particularly in the thickness direction) is likely to occur, so that cracks and cracks are likely to occur. In order to solve such a problem, it is preferable to finish the cooling of the sheet glass at a temperature higher than the glass transition temperature Tg.

  In addition, the width of the cooling promotion region is in the range of 5 to 40% of the width of the upper surface, and the thickness becomes uneven due to poor elongation to the end in the width direction, or the glass is bent into the glass. From the viewpoint of preventing uneven surface irregularities and cracks from occurring on the glass surface. The width of the cooling promotion region is preferably in the range of 10 to 30% of the width of the upper surface, and more preferably in the range of 10 to 25%.

  FIG. 2 shows a state in which the cooling medium supply pipe 4 is inserted and arranged in the hole 14 of the bottom portion 13, but the cross-sectional shape of the cooling medium supply pipe 4 shown here is a semicircular shape, and the arc portion is downward. The flat portion where the discharge port 41 is provided faces upward. However, the cross-sectional shape of the cooling medium supply pipe 4 is not limited to a semicircular shape, and the discharge port 41 is provided and the cooling medium ejected from the discharge port 41 is formed between the cooling medium supply pipe 4 and the inner surface of the hole 14. There is no further limitation as long as it is a structure that discharges to the outside through a gap between them. In addition to the semi-circle, for example, a quadrangle or a triangle can be used.

  The cooling medium supplied from the outside through the inside of the cooling medium supply pipe 4 is discharged from the discharge port 41 toward the inner surface of the hole 14 of the bottom portion 13, strongly cooling the vicinity of the top portion of the inner surface of the hole 41, The gas is exhausted to the outside of the bottom through a gap formed between the cooling medium supply pipes 4. By adopting such a structure, the cooling strength in the vicinity of the discharge port can be locally and selectively increased in the portion of the bottom portion 13 where the hole 14 is provided. Further, the cooling of the portion provided with the hole at the bottom is significantly promoted compared to the portion without the hole. By using the mold 1 and the cooling medium supply pipe 4 described above and selecting the position of the hole 14 in the bottom portion 13 and the arrangement position of the discharge port 41, the cooling promotion region of the bottom portion 13 can be freely set. Further, the supply of the cooling medium to the cooling medium supply pipe 4 can be performed from one end side of the cooling medium supply pipe 4, but can also be performed from both end sides. When supplying the cooling medium from one end side, the other end can be blocked. In the case of performing from both end sides, it is appropriate to supply the cooling medium at the same pressure to both end sides from the viewpoint of uniformly cooling the left and right sides of the cooling promotion region. Alternatively, both ends of the cooling medium supply pipe 4 can be sealed, and a cooling medium supply pipe provided separately at the center can be connected to supply the cooling medium into the cooling medium supply pipe 4. In that case, the cooling medium supply pipe is also inserted into the hole 14 together with the cooling medium supply pipe 4.

  FIG. 3 shows a cooling promotion region in the mold shown in FIGS. However, the reject medium supply pipe 4 shown in FIG. The cooling promotion region includes a position immediately below the orifice and has substantially the same width toward the downstream. When the glass plate to be formed is relatively thin and the flow rate of the molten glass flowing out from the orifice is relatively small, the high-temperature molten glass flowing out from the orifice moves as a whole, that is, in the forming direction. However, the portion in contact with the high-temperature glass at the bottom has substantially the same width as it proceeds in the molding direction. Therefore, by setting this range as the cooling promotion region at the bottom, it is possible to accurately cool the portion in contact with the high temperature glass at the bottom, and to avoid excessively increasing the cooling strength outside the region of the cooling promotion region. In addition, it is possible to effectively prevent the folding of the glass, the unevenness of the tree pattern, and the generation of cracks.

  Furthermore, because it can selectively promote the cooling of the part that is heated intensely by contact with the glass, the temperature distribution of the entire bottom can be reduced, and the deformation of the bottom and the flatness of the glass plate accompanying this deformation are reduced. Such problems can be prevented.

  The region that promotes cooling of the upper surface should be symmetrically provided with respect to a virtual straight line that passes through the position immediately below the orifice and extends in the forming direction, so that the temperature distribution in the width direction of the glass plate is symmetrical with respect to the center position. This is preferable from the viewpoint that uniformity can be maintained. For this purpose, the arrangement of the discharge ports 41 is preferably symmetric with respect to the center line in the width direction of the mold, so that the bottom is cooled symmetrically with respect to the center line in the width direction. be able to. Casting of the molten glass is carried out by flowing the molten glass into the mold from an orifice disposed in the middle upper part between the pair of side walls of the mold. Therefore, since the temperature distribution in the width direction of the glass plate is basically symmetric with respect to the center position in the width direction, according to the above method, cooling can be performed without breaking the symmetry. In addition, the portion immediately below the orifice at the bottom can be additionally cooled strongly in a spot manner.

  The cooling medium is not particularly limited as long as it is a fluid for exchanging heat with the bottom, but a gas, particularly air or nitrogen gas, is preferable because it is easily available and has a low specific heat and a small adjustment resolution.

  It is preferable that the cooling intensity in the cooling promotion region is linearly reflected in an increase or decrease in the supply amount of the cooling medium. To this end, in a mechanism using a cooling medium, when there are a plurality of cooling medium discharge ports, if the distance between the discharge port and the object to be cooled, i.e., the bottom, differs depending on the hole, the cooling medium may have the same flow rate. Since the effects differ, it is desirable to make the distance between the inner surface of the hole and the discharge port uniform in order to control the cooling strength by changing the size of the discharge port. For example, as shown in FIG. 2, the cross-sectional shape of each cooling medium supply pipe is aligned and the direction of the discharge port of each cooling medium supply pipe is aligned so that the direction of the discharge port does not change in each cooling medium supply pipe. Is preferred.

  Since the glass to be molded does not cause local deformation in the cross section in the width direction, it is preferable to cool the glass so as not to create a temperature sudden change portion (which affects the glass for a long time) at a specific position in the width direction. In particular, in the formation of a thin glass plate, the strength of the glass plate itself is small, and it is easy to deform due to the difference in cooling rate depending on the location. This will cause deformation, which is not preferable. In the present invention, when using a casting mold in which the cooling medium supply pipe 4 interspersed with the discharge ports 41 shown in FIGS. 1 to 3 is inserted into the holes 14 of the bottom portion 13, the bottom 13 is cooled by the cooling medium from the discharge ports 41. The portion can be set to a relatively small area on the upper surface, and the cooling medium can be reliably supplied only to the set position even at a small flow rate. Therefore, such a sudden temperature change portion is unlikely to occur, so that even a thin glass plate can be prevented from being deformed. Further, since the insertion direction of the cooling medium supply pipe 4 is perpendicular to the molding direction, the “time to receive influence (cooling promotion)” of the glass passing over the discharge port 41 is vacant in parallel to the molding direction. It is much shorter than the hole, and even if there is a sudden temperature change portion near the discharge port 41, the glass itself is unlikely to be greatly deformed.

(Second Embodiment)
When the plurality of cooling medium supply pipes have different numbers of discharge ports, the shape, size, and interval of the discharge ports 51 provided in each cooling medium supply pipe 5 are equal, but the discharge ports 51 The number of the cooling medium supply pipes 5 located downstream can be increased so that the width of the cooling promotion region increases intermittently or continuously toward the downstream. FIG. 4 shows six cooling medium supply pipes 5 arranged in parallel so that the discharge ports 51 provided on the side face upward. On the side surface of the leftmost pipe of the six cooling medium supply pipes, the discharge ports 51 are provided at five positions so as to be equally spaced. The number of discharge ports is such that the right adjacent tube sequentially increases by 2 from the left adjacent tube, and the number of discharge ports is 7 sequentially from the tube having the five discharge ports to the right. 9, 11, 13, and 15. Further, FIGS. 5 and 6 show a state in which six cooling medium supply pipes 5 are inserted into the six holes 14. The number of discharge ports 51 can be appropriately selected according to the cooling region. A plurality of cooling medium supply pipes 5 are inserted into the holes 14 of the mold bottom 13, and among the plurality of discharge openings provided in each cooling medium supply pipe, the central discharge opening coincides with the center in the mold width direction. Place each tube in By doing in this way, the width | variety of the cooling promotion area | region extended in a shaping | molding direction can be increased intermittently or continuously toward the downstream. The number and installation positions of the cooling medium supply pipes 5 can be appropriately determined in consideration of the size of the position of the cooling promotion region. There is no limit to the number of discharge ports provided in each cooling medium supply pipe, and the width of the cooling region may be increased downstream.

  As for the position of the cooling promotion region, if a position immediately below the orifice is a start position, a certain position from the position immediately below the orifice toward the molding direction is the final position. The final position is appropriately determined in consideration of the cooling state of the glass to be molded. Specifically, it is preferable that the position where the glass temperature is in the range of glass transition temperature Tg-100 ° C. to Tg + 100 ° C. is the final position. Further, until the lower surface temperature of the glass is cooled in the range of softening point to softening point-300 ° C., preferably in the range of softening point-30 ° C. to softening point-200 ° C., it is set so as to exist in the cooling promotion region. To prevent the film from fusing to the mold and poorly stretched, resulting in uneven thickness, folding into the glass, uneven unevenness and cracks on the glass surface, and warping in the width direction. From the viewpoint of The thickness shape is determined based on the softening point, whereas the warped shape is determined based on the Tg standard. When the wall thickness is relatively large, warp is unlikely to occur because the strength of the sheet glass increases, and conversely, a temperature difference (particularly in the thickness direction) is likely to occur, so that cracks and cracks are likely to occur. In order to solve such a problem, it is preferable to finish the cooling of the sheet glass at a temperature higher than the glass transition temperature Tg.

  In addition, the width of the cooling promotion region is in the range of 10 to 80% of the width of the upper surface at the start position. It is appropriate from the viewpoint of preventing folding inside and uneven unevenness and cracks on the glass surface. The width of the cooling promotion region at the start position is preferably in the range of 15 to 70% of the width of the upper surface, and more preferably in the range of 15 to 60%. The width of the cooling promotion region in the final position is appropriately in the range of 60 to 90% of the width of the upper surface from the viewpoint of preventing the occurrence of warpage in the width direction. Further, the ratio (final / start) of the width of the cooling promotion region at the start position to the width of the cooling promotion region at the final position can be, for example, in the range of 2-30, preferably in the range of 4-15. It is.

  FIG. 5 shows a state in which the cooling medium supply pipe 5 is inserted and arranged in the hole 14 of the bottom portion 13, but the sectional shape of the cooling medium supply pipe 5 shown here is a semicircular shape, and the arc portion is downward. The flat part where the discharge port 51 is provided faces upward. However, the cross-sectional shape of the cooling medium supply pipe 5 is not limited to a semicircular shape, and the discharge port 51 is provided, and the cooling medium ejected from the discharge port 51 is formed between the cooling medium supply pipe 5 and the inner surface of the hole 14. There is no further limitation as long as it is a structure that discharges to the outside through a gap between them. In addition to the semi-circle, for example, a quadrangle or a triangle can be used.

  The cooling medium supplied from the outside through the inside of the cooling medium supply pipe 5 is discharged from the discharge port 51 toward the inner surface of the hole 14 of the bottom portion 13, strongly cooling the vicinity of the top portion of the inner surface of the hole 51, The gas is exhausted to the outside of the bottom through a gap formed between the cooling medium supply pipes 5. By adopting such a structure, the cooling strength in the vicinity of the discharge port can be locally and selectively increased in the portion of the bottom portion 13 where the hole 14 is provided. Further, the cooling of the portion provided with the hole at the bottom is significantly promoted compared to the portion without the hole. By using the mold 1 and the cooling medium supply pipe 5 described above and selecting the position of the hole 14 in the bottom portion 13 and the arrangement position of the discharge port 51, the cooling promotion region of the bottom portion 13 can be freely set. In addition, the supply of the cooling medium to the cooling medium supply pipe 5 can be performed from one end side of the cooling medium supply pipe 5, but can also be performed from both end sides. When supplying the cooling medium from one end side, the other end can be blocked. In the case of performing from both end sides, it is appropriate to supply the cooling medium at the same pressure to both end sides from the viewpoint of uniformly cooling the left and right sides of the cooling promotion region. Alternatively, both ends of the cooling medium supply pipe 5 can be sealed, and a cooling medium supply pipe provided separately in the center can be connected to supply the cooling medium into the cooling medium supply pipe 5. In that case, the cooling medium supply pipe is also inserted into the hole 14 together with the cooling medium supply pipe 5.

  FIG. 6 shows the cooling promotion region in the mold shown in FIGS. 4 and 5 when seen in a plan view. The cooling promotion region includes a position immediately below the orifice, and the width increases intermittently or continuously toward the downstream. When the glass plate to be formed is relatively wide, the thickness is relatively thin, and the flow rate of the molten glass flowing out from the orifice is relatively large, the high-temperature molten glass flowing out from the orifice is generally downstream, That is, it expands in the width direction as it moves in the molding direction, and the portion that contacts the high temperature glass at the bottom also expands in the width direction as it proceeds in the molding direction. Therefore, by setting this range as the cooling promotion region at the bottom, it is possible to accurately cool the portion in contact with the high temperature glass at the bottom, and to avoid excessively increasing the cooling strength outside the region of the cooling promotion region. In addition, it is possible to effectively prevent the folding of the glass, the unevenness of the tree pattern, and the generation of cracks.

  Furthermore, because it can selectively promote the cooling of the part that is heated intensely by contact with the glass, the temperature distribution of the entire bottom can be reduced, and the deformation of the bottom and the flatness of the glass plate accompanying this deformation are reduced. Such problems can be prevented.

  The region that promotes cooling of the upper surface should be symmetrically provided with respect to a virtual straight line that passes through the position immediately below the orifice and extends in the forming direction, so that the temperature distribution in the width direction of the glass plate is symmetrical with respect to the center position. This is preferable from the viewpoint that uniformity can be maintained. For this purpose, the arrangement of the discharge ports 51 is preferably symmetric with respect to the center line in the width direction of the mold, and by doing so, cooling of the bottom is performed symmetrically with respect to the center line in the width direction. be able to. Casting of the molten glass is carried out by flowing the molten glass into the mold from an orifice disposed in the middle upper part between the pair of side walls of the mold. Therefore, since the temperature distribution in the width direction of the glass plate is basically symmetric with respect to the center position in the width direction, according to the above method, cooling can be performed without breaking the symmetry. In addition, the portion immediately below the orifice at the bottom can be additionally cooled strongly in a spot manner.

  The cooling medium is not particularly limited as long as it is a fluid for exchanging heat with the bottom, but a gas, particularly air or nitrogen gas, is preferable because it is easily available and has a low specific heat and a small adjustment resolution.

  It is preferable that the cooling intensity in the cooling promotion region is linearly reflected in an increase or decrease in the supply amount of the cooling medium. To this end, in a mechanism using a cooling medium, when there are a plurality of cooling medium discharge ports, if the distance between the discharge port and the object to be cooled, i.e., the bottom, differs depending on the hole, the cooling medium may have the same flow rate. Since the effects differ, it is desirable to make the distance between the inner surface of the hole and the discharge port uniform in order to control the cooling strength by changing the size of the discharge port. For example, as shown in FIG. 5, the cross-sectional shape of each cooling medium supply pipe is aligned and the direction of the discharge port of each cooling medium supply pipe is aligned so that the direction of the discharge port does not change in each cooling medium supply pipe. Is preferred.

  Since the glass to be molded does not cause local deformation in the cross section in the width direction, it is preferable to cool the glass so as not to create a temperature sudden change portion (which affects the glass for a long time) at a specific position in the width direction. In particular, in the formation of a thin glass plate, the strength of the glass plate itself is small, and it is easy to deform due to the difference in cooling rate depending on the location. This will cause deformation, which is not preferable. In the present invention, when using a casting mold in which the cooling medium supply pipe 5 interspersed with the discharge ports 51 shown in FIGS. 4 to 6 is inserted into the holes 14 of the bottom portion 13, the bottom 13 is cooled by the cooling medium from the discharge ports 51. The portion can be set to a relatively small area on the upper surface, and the necessary cooling amount can be reliably supplied to the set position by controlling the flow rate of the cooling medium. Therefore, such a sudden temperature change portion is unlikely to occur, so that even a thin glass plate can be prevented from being deformed. Furthermore, since the insertion direction of the cooling medium supply pipe 5 is perpendicular to the molding direction, the “time to receive influence (cooling promotion)” of the glass passing over the discharge port 51 is vacant in parallel to the molding direction. The glass itself is much shorter than the hole, and even if there is a sudden temperature change near the discharge port 51, the glass itself is unlikely to be greatly deformed.

[Glass plate manufacturing method]
The manufacturing method of the glass plate of this invention is a method using said glass plate manufacturing apparatus. The manufacturing method of the present invention includes the steps of preparing the manufacturing apparatus by determining the number and arrangement positions of the cooling medium supply pipes arranged in the manufacturing apparatus and the number of discharge ports of the cooling medium supply pipe, and the manufacturing apparatus prepared In the mold, the molten glass flowing out from the orifice is continuously cast into the mold, and the glass cast along the both side walls is moved from the upstream side to the downstream side in one direction (molding direction). A step of continuously forming a glass plate. Further, the casting of the molten glass and forming into a flat plate shape is a region extending in the forming direction from the position immediately below the orifice and the position directly below the orifice when the upper surface is viewed in plan (referred to as a cooling promotion region). ) While locally cooling.

  In the production method of the present invention, the above glass plate production apparatus is used prior to the production of the glass plate, but depending on the type of glass to be molded and the molding conditions, the number and position of through holes provided in the bottom of the mold, and through The number and positions of the cooling medium supply pipes inserted into the holes and the number of discharge ports of each cooling medium supply pipe are set.

  These conditions can be broadly divided into cases where the width of the glass plate to be formed is relatively wide, the thickness of the glass plate to be formed is relatively thin, and the flow rate of the molten glass flowing out from the orifice is relatively small (embodiment). A) and a case where the flow rate of the molten glass flowing out from the orifice is relatively large (embodiment B). In the case of the embodiment A, the number and positions of the cooling medium supply pipes arranged in the manufacturing apparatus and the number of discharge ports of the cooling medium supply pipes are substantially the same in the cooling direction in the molding direction. It is preferably determined to have a width. In this case, the manufacturing apparatus of the first embodiment can be used. In the case of Embodiment B, the number and position of the cooling medium supply pipes arranged in the manufacturing apparatus, and the number of discharge ports of the cooling medium supply pipes are such that the cooling promotion region is intermittent in width in the molding direction. It is preferably determined to increase continuously or continuously. In this case, the manufacturing apparatus of the second embodiment can be used.

(Embodiment A)
In the case of Embodiment A, the desired effect can be obtained even if the flow rate of the molten glass flowing out from the orifice is relatively small. When the thickness of the glass plate to be molded is relatively thin, for example, the width is 100 mm or more, preferably 150 mm or more, more preferably 200 to 300 mm, and the thickness is 6 to 30 mm, preferably 6 to 20 mm. The width / thickness is in the range of 3-50, preferably 5-40, more preferably 10-40. The flow rate of the molten glass flowing out from the orifice can be, for example, in the range of 20 to 140 mL / min, preferably in the range of 30 to 120 mL / min, and more preferably in the range of 30 to 80 mL / min.

(Embodiment B)
In the case of Embodiment B, the desired effect can be obtained even if the flow rate of the molten glass flowing out from the orifice is relatively large. Is in the range of 100 mm or more, preferably 120 mm or more, preferably 150 to 300 mm, the thickness is 6 to 30 mm, preferably 8 to 20 mm, and the width / thickness is in the range of 3 to 80, preferably 5 to 5 mm. 40, more preferably in the range of 10-30. The flow rate of the molten glass flowing out from the orifice can be, for example, more than 140 mL / min, preferably in the range of 140 to 500 mL / min, more preferably in the range of 200 to 800 mL / min.

  The glass plate formed by the method for producing a glass plate of the present invention is drawn out from the mold along the moving direction, and is transferred to the annealing furnace, for example, by a conveyor. In the process of passing through the annealing furnace, the glass plate is gradually cooled and moved out of the annealing furnace. The glass is moved in the mold by transferring the formed glass plate in the moving direction on the conveyor as described above. The glass plate is a continuous plate from the mold through the annealing furnace until it exits the annealing furnace. And it cut | disconnects in suitable length in the place which came out of the annealing furnace. In this way, plate-like glass can be obtained one after another from one glass plate. The glass plate thus obtained can be divided into glass pieces and used as a glass material for press molding. Details thereof will be described later.

  According to the method for producing a glass plate of the present invention, it is possible to melt the melted optical glass, flow out of a circular orifice, and continuously form it into a plate shape having a uniform thickness. In addition, since the molten glass that has flowed out at a low viscosity (high temperature) is cast into a mold having a flat bottom surface and a side wall parallel to each other across the bottom surface, and is rapidly quenched, it can be applied to optical glass that is easily devitrified. In the case of Embodiment A, this forming method has a lifting amount (volume of molten glass per unit time flowing out from the orifice) of about 20 mL / min to 140 mL / min as described above. In this case, it is over 140 mL / min.

  The main use of the glass plate produced by the method for producing a glass plate of the present invention is an intermediate for obtaining a glass material for press molding. That is, the manufactured glass plate can be cut into a dice-like piece by cutting vertically and horizontally as described later, and then subjected to a barrel polishing step for corner dropping and weight adjustment to be a press-molding material. The obtained material for press molding can be used as an optical component such as a lens by heating and softening and press molding, or by subjecting the press-molded article to grinding and polishing.

  In such applications, if the thickness of the glass plate material is not uniform, the cutting width must be changed in accordance with the thickness of the part in order to reduce the weight deviation of the small piece as the material for press molding. In addition, not only is it necessary to adjust the wheel interval extremely complicated, but if the cutting width cannot be corrected well, it will result in material loss and further weight adjustment by taking longer barrel polishing time. Because it comes out, the production efficiency is very bad and causes a cost increase, but according to the present invention, since the thickness of the glass plate can be made uniform, even if the glass plate is divided and cut with a constant cutting width, It is possible to suppress an increase in the weight deviation of the cut glass piece.

[Method of manufacturing glass material for press molding]
The present invention also relates to a method for producing a glass material for press molding for press molding by heating and softening. The manufacturing method of the glass material for press molding of this invention produces a glass plate by the method of the said invention, divides | segments the said glass plate, produces several glass piece (glass cut piece), Including processing. The cut piece processing is, for example, polishing processing. A glass piece is polished to obtain a glass material for press molding.

  Below, the specific aspect of the manufacturing method of the glass raw material for press molding of this invention is demonstrated.

  As described above, a diamond wheel, a wire saw, a grindstone, or the like was used as a method of dividing a glass piece (called a cut piece) from a glass plate obtained by cutting an end portion of a glass plate to be supplied. A cutting method, a method of applying a pressure to a glass plate so that a scribing process is performed on a part to be divided to form a marking line, and fracture is extended from the marking line to break the glass can be used. A glass material for press molding can be obtained by subjecting the glass pieces thus divided to polishing such as barrel polishing.

  According to the method for producing a glass plate of the present invention, a glass plate having a uniform thickness can be obtained with little difference in thickness between both ends and the center portion. The volume of the piece can be made to some extent, and the weight deviation of the cut piece can be suppressed without adjusting the cutting width for each cutting location. Therefore, it is possible to reduce the amount of glass that must be removed by barrel polishing in order to equalize the weight and volume of each cut piece, shorten the barrel polishing processing time, and save resources and energy. The cut piece is usually finished into a press-molding material by performing corner cutting and barrel polishing for further reducing the weight deviation. By gently removing the irregularities formed on the upper surface of the glass plate by the above polishing process, it is possible to obtain a glass material for press molding with a substantially smooth surface, but even if some irregularities remain, the stage of grinding and polishing the lens If it is the depth removed by this, there is no problem as a cut piece.

[Manufacturing method of optical components]
The present invention includes a method for manufacturing an optical element, in which a glass optical element is manufactured through steps of heating, softening, and press-molding a glass material. This method is a method of producing a glass material for press molding by the method of the present invention, and heating, softening, and press molding the glass material.

The first aspect of the method for producing an optical component of the present invention is an optical component for obtaining an optical component by heating and press-molding the glass material for press molding produced by the method for producing a glass material for press molding of the present invention. It is a manufacturing method. In this embodiment, an optical component is obtained by so-called precision press molding. In precision press molding, the material for press molding is usually heated in a non-oxidizing atmosphere to a temperature at which a viscosity of 10 ⁵ to 10 ⁸ poise is reached, press-molded with a molding die, and the shape of the molding surface of the molding die is precisely glass. Transfer molding to. The press-molded product thus obtained has high shape accuracy and can be used as it is as an optical component such as a lens.

The second aspect of the method for producing an optical component of the present invention is to heat a glass material for press molding produced by the method for producing a glass material for press molding of the present invention, to produce a glass molded product by press molding, An optical component manufacturing method for obtaining an optical component by subjecting the glass molded product to grinding and / or polishing steps. In this aspect, an optical component is obtained through grinding and polishing after press molding. In such a manufacturing method, generally, a glass material for press molding is heated to a temperature at which a viscosity of about 10 ⁴ to 10 ⁶ poise is obtained in the atmosphere, and press-molded with a molding die. In press molding in the above temperature range, after obtaining a glass molded product that approximates the shape of the target glass article, grinding and polishing are performed, for example, for optical parts such as lenses that require high shape accuracy Can be finished.

  By such a method, optical components such as an aspherical lens, a spherical lens, a lens array, a microlens, a diffraction grating, and a prism can be manufactured with high productivity. If necessary, an optical multilayer film such as an antireflection film may be formed on the surface of the optical component.

[Method for producing thin glass]
The present invention includes a method for producing thin glass. In this method, a glass plate is produced by the method of the present invention, and a thin glass plate is produced from the produced glass plate through a process including lapping. The lapping process is a known processing method, and both main surfaces of the glass plate can be polished to obtain a flat sheet glass having a required thickness.

Example 1
Six cooling pipes each having five discharge ports at an 8 mm pitch are arranged at 0, 30, and 60 mm positions from the orifice position toward the molding direction, with 1000 ° C. optical glass flowing out from the orifice at a flow rate of 60 mL / min. Compressed air of 0.3 MPa was supplied to the cooling pipe at 15, 10 and 5 L / min, respectively, to cool the bottom, and a glass plate having a forming width of 240 mm and a wall thickness of 15 mm was formed. A glass plate having a thickness of 6 mm, a warpage of 0.04 mm, and a tree pattern depth of 0.12 mm could be formed without folding.

Comparative Example 1
In order to form the glass plate using an apparatus as shown in FIG. 5b of Patent Document 1, 150 L / min of compressed air having a minimum cooling amount of 0.3 MPa to prevent fusion at the bottom. As a result, the elongation of the glass deteriorated near the side wall of the mold, resulting in a glass plate having a poor shape with a thickness difference of 1.5 mm in the width direction and a depth of 3.0 mm.

Example 2
6 cooling pipes with 5, 7, 8, 11, 13, and 15 discharge ports at 8 mm pitch, respectively, from the orifice position toward the molding direction from 1100 ° C optical glass flowing out from the orifice at a flow rate of 300 mL / min. Placed at 0 mm, 30 mm, 60 mm, 90 mm, 120 mm, and 150 mm positions, 0.3 MPa compressed air is supplied to the cooling pipe at 30 L / min, 30 L / min, 30 L / min, 20 L / min, 20 L / min, and 15 L / min, respectively. Supplying and cooling the bottom, forming a glass plate with a molding width of 200 mm and a wall thickness of 10 mm, a glass plate with a width direction thickness difference of 0.2 mm, a warp of 0.05 mm, and a tree pattern depth of 0.04 mm. The glass could be stably molded without fusing the glass to the mold and without causing folding.

Comparative Example 2
Next, in order to form a glass plate of the same size using an apparatus as shown in FIG. 5 b of Patent Document 1, 0.3 Lpa of compressed air was supplied to the bottom portion at 700 L / min. The glass flow rate could only be increased to 200 mL / min for fusion to the mold. Moreover, the shape of the glass plate at that time warped at both ends, and the amount of warpage was 2 mm.

  The present invention is useful in the field of producing optical components such as lenses.

1 Mold 11, 11 ′ Side wall 12 Stopper 13 Bottom 14 Hole 2 Glass 3 Orifice 4, 5 Cooling medium supply pipe 41, 51 Discharge port

Claims (13)

Production of a glass plate including a mold having a pair of opposing side walls defining the width of the glass plate and a bottom portion having a surface (hereinafter referred to as an upper surface) for molding one of the two opposing main surfaces of the glass plate A device,
The bottom portion has at least two through-holes therein, which are substantially orthogonal to the side wall and substantially parallel to the top surface, and the through-hole has an opening on a side surface of the bottom portion connected to the outer side surface of the side wall,
The manufacturing apparatus includes a cooling medium supply pipe having at least one discharge port for discharging a cooling medium on a side surface,
The cooling medium supply pipe is arranged so that it can be freely inserted into and removed from the through hole, and at least one of the discharge ports is located in the through hole;
When the cooling medium supply pipe is disposed in the through hole, the glass plate manufacturing apparatus has a size and / or shape that allows the cooling medium discharged from the discharge port to flow out of the through hole from the opening. .   Introducing a cooling medium into the cooling medium supply pipe disposed in the through hole, discharging the cooling medium from the discharge port, cooling the upper surface in the vicinity of the discharge port, It is used for forming the glass plate in the moving direction of the glass by continuously casting into the mold and moving the cast glass in one direction (hereinafter referred to as a forming direction) from the upstream side to the downstream side. The apparatus for producing a glass plate according to claim 1.   3. The plurality of through holes and the cooling medium supply pipes are provided, and the plurality of cooling medium supply pipes have the same number of discharge ports or different numbers of discharge ports. Glass plate manufacturing equipment.   4. The apparatus for producing a glass plate according to claim 3, wherein the plurality of cooling medium supply pipes have different numbers of discharge ports, and the number of discharge ports increases in the forming direction.   The cooling medium supply pipe has a gap through which the cooling medium discharged from the discharge port can flow out of the through hole between the side surface having the discharge port and the inner surface of the through hole facing the side surface. The apparatus for manufacturing a glass plate according to any one of claims 1 to 4.   6. The manufacturing apparatus according to claim 1, wherein the number of the through holes and the cooling medium supply pipe is in a range of 2 to 10.   7. The manufacturing apparatus according to claim 1, wherein the cooling medium supply pipe has a semicircular cross-sectional shape, and the discharge port is provided in a semicircular flat portion. A method for producing a glass plate using the production apparatus according to any one of claims 1 to 7,
A step of preparing the manufacturing apparatus by determining the number and arrangement positions of the cooling medium supply pipes arranged in the manufacturing apparatus and the number of discharge ports of the cooling medium supply pipe;
In the mold of the prepared manufacturing apparatus, the molten glass flowing out from the orifice is continuously cast into the mold, and the glass cast along the both side walls is unidirectional from the upstream side to the downstream side (hereinafter, the molding direction). A step of continuously forming a flat glass plate while moving the glass plate, and the casting of the molten glass and the forming of the flat glass plate are performed when the upper surface of the orifice is viewed in plan view. Performing while locally cooling the area extending in the molding direction from the position directly below and the position immediately below the orifice (hereinafter referred to as cooling promotion area),
The manufacturing method of the glass plate characterized by the above-mentioned.   The number and arrangement positions of the cooling medium supply pipes arranged in the manufacturing apparatus, and the number of discharge ports provided in the cooling medium supply pipes are determined so that the cooling promotion region has substantially the same width in the molding direction. The production method according to claim 8.   The number and position of the cooling medium supply pipes arranged in the manufacturing apparatus, and the number of discharge ports of the cooling medium supply pipes, the width of the cooling promotion region increases intermittently or continuously in the molding direction. 9. The production method according to claim 8, which is determined as follows. In the manufacturing method of the glass material for press molding for heating, softening and press molding,
A method for producing a glass material for press molding, comprising producing a glass plate by the method according to any one of claims 8 to 10, dividing the glass plate to produce a plurality of glass cut pieces, and processing the cut pieces. . In the method of manufacturing an optical element for producing a glass optical element through a process of heating, softening and press molding a glass material,
12. A method for producing an optical element, comprising producing a glass material for press molding by the method according to claim 11, heating, softening, and press molding the glass material.   A method for producing a thin glass, comprising producing a glass plate by the method according to any one of claims 8 to 10 and producing a thin glass from the glass plate through a step including a slicing process.

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