JP2006298736A - Apparatus for forming plate glass, supporting member for apparatus for forming plate glass and method for forming plate glass - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for forming plate glass capable of constantly maintaining a plate thickness, forming dimensions and quality for a long time, a high strength supporting member used in the forming apparatus and a method for forming the plate glass using the forming apparatus. <P>SOLUTION: The apparatus 10 for forming the plate glass is a formed product which has a trough-shaped molten glass supply groove on the top and utilizes both of the side-wall tops of the supply groove as overflow weirs, and in which the outside sections of both of the side walls are brought close to each other so that the cross-section is approximately wedge-shaped. The supporting member is penetrated into the inside of the formed product so that both ends of the supporting member are held. The plate glass is formed with the apparatus by allowing molten glass to overflow over both of the side-wall top ridges and flow downward along the outside sections of the side walls. The supporting member is long and in the shape of a bar with the section modulus of the cross-section of the bar in the range of 1×10<SP>-6</SP>m<SP>3</SP>to 8×10<SP>-3</SP>m<SP>3</SP>. The supporting member for the plate glass forming apparatus has the external surfaces the unevenness of the surface roughness of which is 5 mm or less. By the method for forming the plate glass, the plate glass with a thickness of 3 mm or thinner and a width of 1,500 mm or larger and having a density of 2.9 g/cm<SP>3</SP>or less is formed at 1,000°C or higher with the apparatus. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet glass forming apparatus, and more particularly to an overflow downdraw type sheet glass forming apparatus suitable for forming a sheet glass mounted on a liquid crystal display device.

  Various types of plate glass forming methods are known. In general, an apparatus for forming a sheet glass by the overflow down draw method is shown in FIGS. As shown here, the overflow down-draw type glass sheet forming apparatus has a glass supply groove 1a having a bowl shape with an open upper surface at the top, and overflows two tops corresponding to the end walls of the glass supply groove 1a. And a molded body 1 that has an appearance similar to a cutting edge having a substantially wedge shape by bringing the two outer surfaces 1c of both side walls toward each other toward each other downward, and terminated at the lower end 1d. I have. The molten glass G is continuously supplied from the one end side of the glass supply groove 1a by the molten glass supply pipe 2, and the molten glass temporarily retained in the glass supply groove 1a overflows from the two ridge lines 1e at the tops of both side walls. Furthermore, since the two outer surfaces 1c having a substantially wedge shape sandwiched between the guides 1f on both side walls respectively flow down and merge at the lower end 1d, the plate glass P can be formed by extending the two downwards. The plate glass P thus obtained has high smoothness because the surface thereof is in a state corresponding to a free melting surface at the time of melting, and as shown in FIG. 4C, the central region Pα and both end portions Pβ The thickness becomes a substantially uniform shape.

  The molded body 1 is designed and configured so that the top ridge line 1e on both side walls of the glass supply groove 1a is substantially linear over the entire length, and the molten glass G overflows evenly. However, this type of molded body 1 needs to be configured using a refractory having high corrosion resistance against the molten glass G. For this reason, the molded body 1 is increased in weight, and is disposed so that only both ends of the molded body 1 are supported by the supporting refractory 3, and is continuously exposed to high temperature conditions for a long time during production. As a result, a phenomenon occurs in which, while operating for a long time, it gradually bends downward and deforms due to gravity F. This deformation phenomenon is generally referred to as creep deformation (or simply creep). In order to obtain a sheet glass product having a large area and a large sheet width (for example, 1000 × 1500 mm), a sheet glass P having a large effective width is used. In the case of molding, it is necessary to increase the longitudinal dimension of the molded body 10 (for example, 1800 mm or more), and the amount of creep deformation tends to be further increased. For example, FIGS. 5A and 5B show the molded body 1 that has undergone creep deformation by operating the molding apparatus for a long time. When the molded body 1 undergoes creep deformation, both side walls of the glass supply groove 1a are shown. The top ridge line 1e also bends downward to form a large arcuate curved shape having a convex shape downward, and the overflow amount of the molten glass G overflowing from the ridge line 1e is large in the central region 1g in the longitudinal direction of the molded body 1, It decreases in both end regions 1h. As a result, as shown in FIG. 5C, the formed glass sheet P has a shape in which the thickness of the central portion Pα is thick, the thickness of the peripheral portion Pβ is thin, and the thickness is not uniform. .

  By the way, the plate glass used as a substrate mounted on a liquid crystal display or the like currently has a plate thickness dimension of 0.7 mm, but the required quality of the user for the plate thickness dimension accuracy is very strict. The accuracy is 0.7 ± 0.01 mm. For this reason, when the molded body 1 undergoes creep deformation as described above, the thickness of the plate glass P tends to be non-uniform, and as a result, the production yield at the time of forming the plate glass is significantly reduced.

  Therefore, as a method for solving such a problem, when the glass sheet P requiring such high accuracy is formed, the vicinity of the both end regions 1h of the molten glass is heated or cooled in the vicinity of the lower end 1d of the molded body 1. A method has been adopted, and adjustments have been made so that the thickness of the plate glass P becomes uniform. However, about the adjustment operation of the plate thickness of the plate glass P, not only the adjustment of such heating and cooling can not be sufficiently controlled, but when the molten glass flows down the outer surfaces 1c of the both side walls of the molded body 1, The flow becomes uneven, and as a result, the thickness of the peripheral portion Pβ of the plate glass P is likely to fluctuate. In an extreme case, the molten glass is molded without being sufficiently fused at the peripheral portion Pβ. As a result, there is a problem that the plate glass P is frequently cracked.

Under these circumstances, in Patent Document 1, a through-hole is formed in the length direction of the molded body 1 and a supporting member is inserted into the through-hole, thereby forming a sheet glass molding apparatus that suppresses creep deformation of the molded body 1. was suggested. Further, Patent Document 2 discloses an invention that makes creep deformation difficult by setting the ratio of the total length and height of the molded body 1 within a predetermined range. Furthermore, in patent document 3, the overflow amount of molten glass is easily adjusted by forming the top ridge lines of both side walls of the overflow weir in advance so as to bend downward in the start end region and / or end region in the flow direction of the molten glass. An invention that could be done was also disclosed.
JP-A-11-246230 JP 2004-315286 A JP 2004-315287 A

However, the inventions made so far are not sufficient. For example, to obtain a thin plate with a larger area in a highly homogeneous state, or to increase the manufacturing index from the viewpoint of improving manufacturing efficiency, it can withstand the load of mass production by realizing a higher glass forming speed. However, the present inventor has a problem in that it does not have sufficient technical accumulation to produce a large area of thin glass with high homogeneity and cannot meet various requirements. As a plate glass manufacturing device that does not impair the molding quality of large-area plate glass according to the situation and enables mass production over a long period of time, the plate glass molding device has the ability to mold plate glass in order to realize high plate glass molding dimension quality. It is improved and can be mounted on a flat glass molding device, especially a liquid crystal display device, which can maintain stable plate thickness molding dimension quality over a long period of time. An overflow downdraw type plate glass forming apparatus suitable for forming a sheet glass, a high-strength support rod used in such a plate glass forming apparatus, and a method for forming a plate glass using the plate glass forming apparatus are provided. Let it be an issue.

That is, the sheet glass forming apparatus of the present invention has a bowl-shaped molten glass supply groove having an opening at the top, the tops of both side walls of the glass supply groove are used as overflow weirs, and the outer surface portions of both side walls are cross-sectioned. Is provided with a molded body in which the outer surfaces of both side walls approach each other downward and are terminated at the lower end so as to be substantially wedge-shaped, and are inserted into the through-holes inside the molded body with a support member, and both ends of the support member are Hold by the holding table, continuously supply molten glass from one end of the glass supply groove, overflow from the top ridge line of both side walls, flow down along the outer surface of both side walls, and join at the substantially wedge-shaped lower end to form a sheet glass A flat glass forming apparatus, characterized in that the support member is in the shape of a long bar, and the section modulus of the bar cross section is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ .

Here, there is a bowl-shaped molten glass supply groove having an opening at the top, the tops of both side walls of the glass supply groove are used as overflow weirs, and the outer surface of both side walls are arranged on both sides so that the cross section is substantially wedge-shaped. The outer surface of the wall is made to approach each other downward, and the molded body is terminated at the lower end, and both ends of the support member inserted into the through-hole inside the molded body are held by the holding base, and the molten glass is A glass sheet forming apparatus for continuously forming glass sheets by forming a glass sheet by continuously supplying from one end of the glass supply groove, overflowing from the top ridges of both side walls, flowing along the outer surface of both side walls, and joining at a substantially wedge-shaped lower end. Is a long bar shape and the section modulus of the bar cross section is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ , the molten glass overflows the top of both end walls and The cross-sectional shape that flows along the About a molded body that is configured to form a sheet glass under the molded body using a long molded body having heat resistance that is inserted into a hole penetrating the molded body to support the molded body It represents that the value of the section modulus with respect to the cross section of the supporting bar has a range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ .

The section modulus of the rod section of the support rod is uniquely determined by the shape of the section of the rod. Specifically, the second moment of the section about the axis passing through the centroid of the rod section is calculated from the axis to the section of the rod section. The section modulus is divided by the maximum distance to the surroundings. The centroid is the position where the cross-sectional primary moment for any axis passing through one point is 0. The cross-sectional secondary moment subdivides the rod cross-section into a small area, and the square of the distance to the axis is divided into the small area. The value obtained by adding the multiplied values for the total cross-sectional area is shown. If the section modulus is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ , the weight of the molded body that is applied to the molded body is opposed to the weight of the molten glass without bending. The initial design shape can be maintained while being maintained at a high temperature of 1000 ° C. or higher.

The reason why the section modulus is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ is that when the section modulus is smaller than 1 × 10 ⁻⁶ m ³ , melting is performed in addition to the weight of the compact at a temperature of 1000 ° C. or more. Since it may be difficult to maintain the same shape for a long time in a state where the weight of the glass is applied, it is not preferable. On the other hand, when the section modulus is larger than 8 × 10 ⁻³ m ³ , the weight of the support rod becomes too large, and thus a high cost is required to form a basic structure for supporting both the support rod and the molded body. Therefore, more preferably, the range of the section modulus is in the range of 9 × 10 ⁻⁶ m ³ to 1 × 10 ⁻³ m ³ .

  In addition, the long rod-shaped support member of the sheet glass forming apparatus of the present invention can be adopted in any cross-sectional shape within the above-described range of the section modulus. Since the depression-shaped cross section causes local stress concentration, the radius of curvature of the cross-sectional contour shape is preferably 5 mm or more, and more preferably 20 mm or more.

  Here, the long rod-shaped support member is a material that has fire resistance in a temperature range of 1000 ° C. to 1350 ° C., and is difficult to cause plastic flow and deformation of the outer shape, regardless of the material. Preferably there is. For example, silicon carbide (SiC) fine ceramics, silicon nitride (SiN) fine ceramics, zirconia (ZrO2) fine ceramics, aluminum nitride (AlN) fine ceramics, tungsten (W) and molybdenum (Mo) High density alloy materials are preferred.

  In addition, the long bar-shaped support member according to the sheet glass forming apparatus of the present invention can be used in combination with other reinforcing methods employed to reinforce the sheet glass forming apparatus. It does not interfere with other effective means such as deformation and changes in the support structure.

  Further, as the refractory constituting the molded body mounted on the sheet glass forming apparatus of the present invention, a fired refractory, a non-fired refractory, an amorphous refractory having excellent heat resistance and high temperature strength are suitable. More specifically, silica refractories, clay refractories, high alumina refractories, silicon carbide refractories, chrome refractories, magnesia refractories, magnesia refractories, dolomite refractories, sillimanite refractories, Cyanide alumina refractories, mullite refractories, zirconia refractories, cordierite refractories, castable refractories, plastic refractories and the like can be used. In addition to these refractories, it is possible to use fused quartz refractories, synthetic quartz refractories, various fiber boards, and irregular refractory fiber materials, and alloys containing platinum group elements as main components, such as platinum alloys. Heat-resistant noble metals such as can be used. These molded body constituent materials can be used as long as they can sufficiently realize the functions of the molded body, whether used alone or in a plurality of types.

  In addition to the above, the sheet glass forming apparatus of the present invention is preferably a structure in which the support member has a hollow portion.

  Here, the structure in which the support member has a hollow portion means that the support member has a structure having a hollow portion, and there may be one or a plurality of hollow portions. Any shape may be used as long as the support member has a desired strength. The cavity may be open or closed, and may have any opening when in the open state. The size of the cavity is not particularly limited, but it is preferable that the weight of the support member is 90% or less on the basis of the state without the cavity part by having the cavity part.

  In the case of having a plurality of hollow portions, it is often convenient in design to have a structure having a plurality of hollow portions of the same shape, and there is also a merit that it is easy to mold even when a hollow portion is intentionally provided. This is preferable.

  The hollow portion can be filled with a plurality of heat-resistant materials, insulating materials, or lightweight structure materials such as ceramic fibers as necessary. Such a filling structure is preferable because sufficient strength can be compensated even when there is a processing strain or the like on the surface of the cavity while being held at a high temperature. Moreover, it is possible to prevent the durability of the support member from being impaired by causing the support member to be heated more than necessary by flowing a specific fluid medium in the hollow portion as necessary. As a fluid medium, a gas having poor reactivity such as helium, argon, nitrogen, carbon dioxide, or the like, or conversely, inside the cavity of the support member is oxidized atmosphere such as oxygen, water vapor, air, hydrogen, carbon monoxide, etc. By using a reducing atmosphere, it is possible to cover structural defects on the cavity surface with the reaction layer. The fluid medium that has been preheated to a predetermined temperature can be fluidized, and the medium once fluidized can be recovered and reused.

  Further, the surface of the cavity can be coated with other materials according to various purposes on the surface for the purpose of improving its strength, and various ceramic coating materials, heat-resistant metal materials, plating materials, etc. It can be coated with an appropriate thickness. As a coating method, methods such as spray-up, dipping, brush coating, and vapor deposition are possible.

  In addition to the above, the plate glass forming apparatus of the present invention is preferably provided with a structure in which the support member has a recess and / or a groove.

  Here, the structure in which the support member has a recess and / or a groove means that the surface of the support member has an intentional design local recess or a long recess. It means that there is something.

  The depth of the dent and the area of the dent are not particularly limited as long as the physical or chemical durability of the support rod is not impaired by the presence of the dent.

  As a method for forming the depression, for example, a mold or a press die that forms a depression when using various molding methods such as cast molding and press molding in advance, or by firing, sintering, casting, or the like is used. It is formed by polishing and cutting the surface of the support rod, and adopts a shape that forms a groove as a die shape when performing pultrusion molding or extrusion molding, and the roller shape at the time of rolling molding is a groove It is possible to employ a material that forms a film.

  In addition, the support member for a sheet glass forming device of the present invention has an uneven surface of 5 mm or less, and is mounted on the plate glass forming apparatus described above.

  Here, the unevenness of the surface roughness of the outer surface is 5 mm or less, and when mounted on the plate glass forming apparatus described above, the support member for the plate glass forming apparatus of the present invention has a surface roughness of 10 mm. It means that the length is unevenness of 5 mm or less. If the unevenness becomes larger than 5 mm, there is a greater risk of generating surface defects such as chipping and cracking due to the unevenness in the surface portions of both the support member and the molded body when the support rod is inserted into the molded body. Therefore, it is not preferable.

  The surface roughness can be measured using a general stylus type or optical surface roughness measuring device or the like.

  In addition, it is preferable that the support member for a glass sheet molding apparatus of the present invention has a ratio of Young's modulus of the support member to Young's modulus of the constituent material constituting the molded body in the range of 1 to 10.

  Here, the ratio of the Young's modulus of the supporting member to the Young's modulus of the constituent material constituting the constituent material molded body is in the range of 1 to 10 means that the elastic modulus of the supporting member is the refractory material forming the molded body. This indicates that it has a value equal to or greater than the elastic modulus and has an elastic modulus of 10 times or less compared to the Young's modulus of the refractory material forming the molded body.

  At least Young's modulus (also called modulus of elasticity and longitudinal elastic modulus) is equal to or greater than the refractory material of the molded body, making it difficult for the external force to deform more easily than the refractory material. This is preferable because it can be supported. On the other hand, if it exceeds 10 times, there are many cases where the heat resistance is disturbed, and the improvement in performance obtained for the cost of preparing such a material becomes poor, which is not preferable.

  As a method for measuring the Young's modulus, a known method can be adopted, and a static measurement method, a lateral vibration method, or an ultrasonic method can be adopted. As a specific standard regarding measurement, for example, it can be measured by conforming to JIS R1602 (elastic modulus test method of fine ceramics).

The plate glass forming method of the present invention has the above-described plate glass forming apparatus, and has a plate thickness dimension of 3 mm or less, a width dimension of 1500 mm or more, and a density of 2 in a temperature environment of 1000 ° C. or more. It is characterized by forming a sheet glass of .9 g / cm ³ or less.

Here, using the plate glass forming apparatus described above, in a temperature environment of 1000 ° C. or higher, the plate thickness dimension is 3 mm or less, the width dimension is 1500 mm or more, and the density is 2.9 g / cm ³ or less. Is formed by supplying molten glass to the above plate glass forming apparatus and having an outer shape with a plate size of 1500 mm or more and a plate thickness of 3 mm or less at a temperature of 1000 ° C. or higher, and at room temperature (25 ° C.). The sheet glass forming apparatus is capable of continuously forming plate glass having a density of 2.9 g / cm ³ or less.

  As the material of the plate glass formed by the present invention, any material can be used. However, glass materials such as borosilicate glass, non-alkali glass, and aluminosilicate glass can be formed by this apparatus. Is preferred. Borosilicate glass is an oxide glass mainly composed of boron and silicon, and alkali-free glass contains substantially no alkali metal element, that is, sodium, potassium, lithium, which are alkali metal elements in the glass composition. Such an element is a glass material with an oxide conversion of 0.1% by mass or less, and the aluminosilicate glass is an oxide glass material mainly composed of aluminum and silicon.

  The thin glass having the glass material as described above is, for example, a thin glass for a liquid crystal display device, a cover glass for a solid-state imaging device represented by CMOS or CCD, a plate glass for field emission, a cover glass for EL, a bandpass filter, etc. It is suitable for use as glass for optical filters, glass substrate glass for chip-on-glass use, and the like.

  Further, if a preferable material other than the above is selected as the plate glass formed in the present invention, it can be applied to other than the above-described thin glass for a liquid crystal display device. It can also be used as required for thin glass sheets for display devices.

  In addition, the plate glass formed using the plate glass forming apparatus of the present invention has a large appearance with an arbitrary length dimension with a width of 1500 mm or more, and a plate thickness dimension of 3 mm or less. It is suitable for forming a sheet glass having such a thin shape.

  The sheet glass forming method of the present invention is characterized in that a thin sheet glass for mounting on a liquid crystal display device is continuously formed by a downward extending forming means.

  Here, the continuous molding of the thin glass for mounting the liquid crystal display device by the downward stretch molding means is, as a molding method used in the stage of molding the sheet glass, overflow down draw method, slot down draw method, or A method of forming a glass sheet in a high temperature state, such as a roll-out method, while applying a force to be sent downward while stretching is adopted, and such a forming method is suitable in the present invention. And by adopting these forming methods, it becomes possible to produce a thin glass plate with good surface accuracy.

  In addition, continuous molding of a thin glass for mounting a liquid crystal display device means that, for example, a thin glass used as a liquid crystal substrate glass on which an active matrix type thin film transistor (Thin Film Transistor, abbreviated TFT) is mounted. It represents continuous molding. If it is a TFT system, it does not relate to the difference in members such as amorphous silicon and polysilicon.

(1) As described above, the sheet glass forming apparatus of the present invention has a bowl-shaped molten glass supply groove having an open top at the top, and the tops of both side walls of the glass supply groove serve as overflow weirs. The outer surface of the wall is provided with a molded body in which the outer surfaces of both side walls approach each other downward and are closed at the lower end so that the cross section is substantially wedge-shaped, and is inserted into the through hole in the molded body with a support member. , Hold both ends of the support member on the holding base, continuously supply molten glass from one end of the glass supply groove, overflow from the top ridge line of both side walls, flow down along the outer surface of both side walls, and join at the lower edge of the wedge shape A flat glass forming apparatus for forming a flat glass, wherein the support member has a long bar shape and the cross section coefficient of the bar cross section is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ^3. Exposed to a temperature environment over 1000 ° C over time However, it is possible to suppress the central portion in the longitudinal direction of the molded body from being deformed and drooping downward due to creep deformation with time, and to reduce the risk that the thickness of the thin glass sheet to be formed will change over time. Therefore, it is possible to continue to maintain the formation of a stable glass sheet.

  (2) Further, in addition to the above, the sheet glass forming apparatus of the present invention can reduce the weight of the support member if the support member has a hollow portion, so that an overload is applied to the formed body. In addition, the weight increase due to the use of the support member can be suppressed, the strength of the entire molded body including the support member can be set to a sufficiently high value, and a molding apparatus having a stable strength can be realized. It can be done.

  (3) Further, in the sheet glass forming apparatus of the present invention, in addition to the above, if the support member has a structure having a recessed portion and / or a groove portion, a physical shape sufficient to resist bending stress applied to the formed body, that is, structural Therefore, it is possible to minimize the change in the shape of the molded body.

  (4) Since the support member for a sheet glass forming apparatus of the present invention has a surface roughness unevenness of 5 mm or less on the outer surface and is mounted on the plate glass forming apparatus described above, the sheet glass forming apparatus of the present invention is assembled. In the process of inserting the support member into the molded body, it is possible to prevent surface defects from occurring on the surface of the molded body or the surface of the support member.

  (5) Moreover, if the Young's modulus of a constituent material is in the range of 150 to 300 GPa, the support member for a sheet glass forming apparatus of the present invention is generated in the support member in the longitudinal direction by the force applied to the support member from the outside. The amount of bending of the central portion can be made appropriate, and the mechanical performance required for the support member can be reliably realized.

(6) The plate glass forming method of the present invention uses the above-described plate glass forming apparatus, has a plate thickness dimension of 3 mm or less and a width dimension of 1500 mm or more in a temperature environment of 1000 ° C. or higher, and a density. Is used to mold a sheet glass of 2.9 g / cm ³ or less, so that it can meet the customer's demands for high dimensional accuracy, especially surface quality such as bending, distortion and waviness of the sheet glass surface even for large sheet glass. It is possible to easily form a plate glass having such accuracy.

  (7) The plate glass forming method of the present invention is an appearance required for a thin glass to be mounted on a liquid crystal display device, as long as the thin glass for mounting the liquid crystal display device is continuously formed by a downward stretch forming means. It is possible to continue to form a high-quality molded product for a long time, and it is possible to save labor for management of manufacturing equipment and management of molding conditions of sheet glass.

  The plate glass shaping | molding apparatus of this invention, the supporting member used for the apparatus, and also the plate glass shaping | molding method which uses a plate glass shaping | molding apparatus are demonstrated based on an Example.

  An example of the sheet glass forming apparatus of the present invention is shown in FIGS. This apparatus is used for forming a thin glass sheet having a thickness of 3 mm or less to be mounted on a TFT liquid crystal display device.

The molded body 10 in FIG. 1A is composed of a zirconia refractory (density 4.0 g / cm ³ , Young's modulus 142 GPa), and as shown in FIG. It has a bowl-shaped molten glass supply groove 10a having a substantially V-shape in an open state at its top, and the tops of both end walls of the glass supply groove 10a serve as two overflow weirs 10b. Under the overflow weir 10b, the outer surfaces 10c of the two side walls are brought close to each other and finally terminated at the lower end 1d. The overall size of the molded body 10 is 2500 mm in total length in the longitudinal direction, 700 mm in height, 250 mm in width, and has a hole 10n penetrating in the longitudinal direction of the molded body. The hole 10n has a horizontal dimension of 70 mm and a vertical dimension of 180 mm, and the inner surface of the through-hole 10n has been subjected to a drilling process after being subjected to a drilling process on a molded body produced by firing, The surface roughness is adjusted so that the unevenness is 2 mm or less.

A support member 30 made of high-density silicon carbide (SiC) refractory is inserted into the through-hole 10n from one side of the through-hole 10n, and the molded body 10 is held by the support member 30. As shown in the perspective view of FIG. 2, the support member 30 has a structure in which a plurality of long gaps 41 having a rectangular cross section are arranged inside, and its section coefficient is 1.1 × 10 ^−4. At m ³ , the surface roughness unevenness of the outer surface of the support member 30 is blasted so as to be 2 mm or less.

  In the molten glass supply groove 10a of the molded body 10, a molten glass supply pipe 20 for supplying the molten glass G to the molten glass supply groove 10a is disposed at one end in the longitudinal direction. The molten glass G heated to a homogeneous state flows into the molten glass supply groove 10a through the molten glass supply pipe 20. And the molten glass G which flowed into the molten glass supply groove | channel will stay in the molten glass supply groove | channel 10a. The molten glass supply groove 10a is formed with an inclined floor surface so that the side on which the molten glass supply pipe 20 is disposed is low and the other long side of the supply groove 10a is at the upper position.

  The overflow weir 10b of the molten glass supply groove 10a is designed and molded so that the ridges on both side walls have an optimum shape so as to have a shape suitable for continuously flowing out an appropriate amount of the molten glass G. It is also possible to cover the surface with a refractory metal for the purpose of improving the high temperature durability of the ridge line portion 10e and the corrosion resistance against the molten glass.

  In addition, the lower end 10d where the two side wall surfaces 10c of the molded body 10 intersect is such that the molten glass G flowing down along the side wall surface is fused to form one sheet glass P as shown in FIG. It has a sharp shape. The side wall guides 10f are made of platinum or an alloy material containing platinum, and are disposed at both ends of the molten glass supply groove 10a, the two side wall surfaces 10c, and the lower end 10d of the molded body 10, respectively. It functions to determine the width of the molten glass when flowing down the wall surface 10c.

  Next, a method of forming a thin glass mounted on a liquid crystal display device by the above-described flat glass forming apparatus will be exemplified.

  First, in a glass melting tank (not shown) equipped with a high-temperature heating facility, a glass raw material prepared in advance so as to have an alkali-free glass composition (Nippon Electric Glass Co., Ltd., glass OA-10 composition) is melted. After obtaining the homogeneous molten glass G by the refining process, the obtained molten glass G is introduced into the molten glass supply groove 10a through the molten glass supply pipe 20. The molten glass G staying in the molten glass supply groove 10a overflows the two side wall top ridges 10e of the molded body 10, that is, overflows and flows down along the outer surfaces 10c of the both side walls of the molded body. The sheet glass P is formed by being continuously stretched by using a heat-resistant roller (not shown) which is fused at the lower end 10d of 10 and provided further below.

  In the case of a molded body composed only of zirconia refractories as in the past, the outer dimensions of the molded body gradually deform due to the creep phenomenon caused by the high temperature use of the refractory constituting the molded body. Since the central part of the ridge side wall top part ridge line is in a shape drooping downward, the thickness of the formed sheet glass is biased. On the other hand, by using the sheet glass forming apparatus of the present invention, even if the molded body 10 is used until the time when the sag of the central part of the ridge side wall top ridge line of the molded body becomes clear in the conventional molded body, there is no problem. Such a deformation did not occur, and the period during which the molded body 10 was subjected to the normal forming of the plate glass P was extended, and the plate glass P having a stable quality could be formed over a long period of time. The formed plate glass P has no plate thickness difference between the central portion Pα of the plate glass and the peripheral portion Pβ of the plate glass, and has a plate thickness of 0.7 ± 0.01 mm and an effective width of about 2100 mm. There was no problem related to dimensions such as meat, the surface state of the plate glass was also good, and it was suitable as a plate glass used in applications mounted on TFT liquid crystal display devices.

  Next, the support members for supporting the sheet glass forming apparatus of the present invention are shown in the cross-sectional views of FIGS. 3A, 3B, 3C, and 3D having a cross-sectional structure different from that of the first embodiment.

The support member 40a shown in FIG. 3A is made of the same silicon carbide refractory as in the first embodiment. The cross-sectional contour shape is substantially T-shaped, and the rectangular shape is changed as the contour shape is changed. The arrangement of the long gaps 41 having a cross section of the shape is also changed, and the section modulus thereof is 3.5 × 10 ⁻⁴ m ^3, which is the groove bottom surface of the molded body 10 as compared with the first embodiment. In the case of a molded body having a wide width, the shape is particularly suitable. Further, the support member 40b in FIG. 3B is formed by using the same material as that of the first embodiment, and the section of the long gap 41 is substantially triangular, and its section coefficient is 2.1. × 10 ⁻⁴ m ³ , and the contour shape of the support member 40b has a substantially hexagonal shape. Further, the support member 40c of FIG. 3C has a substantially trapezoidal cross-sectional shape, and has a long gap portion 40d having an elliptical cross section inside thereof, and its cross section coefficient is 8.5. × 10 ⁻⁴ m ³ . FIG. 3D shows a cross-sectional structure having two grooves 42 parallel to both side surfaces of the support member, and the cross-sectional coefficient thereof is 2.8 × 10 ⁻⁴ m ³ .

  For any of the supporting members, it is possible to fill the gap with a lightweight refractory material or to flow a cooling medium such as an inert gas. In addition, the supporting members of the present invention are all for supporting the molded body of the plate glass manufacturing apparatus, but can be used as other structural members of the glass manufacturing apparatus as necessary, and are structurally weak parts. It can also be used as one used to reinforce.

It is explanatory drawing of the plate glass shaping | molding apparatus of this invention, (A) is a top view, (B) is sectional drawing of the XX plane of (A) figure, (C) is the YY plane of (A) figure. A sectional view is shown. The perspective view of the supporting member mounted in the plate glass shaping | molding apparatus of this invention is represented. Sectional drawing of the other supporting member mounted in the plate glass shaping | molding apparatus of this invention is represented. (A) is a support member having a cross section in which an array of rectangular cavities is arranged in a T-shape, (B) is a support member having a cross section of a triangular cavity, and (C) is an elliptical cavity. A support member having a cross section, (D) represents a support member having two grooves on both side surfaces of the support member. It is explanatory drawing at the time of manufacture of the conventional plate glass shaping | molding apparatus, (A) is a top view, (B) is sectional drawing of the XX plane of (A) figure, (C) is YY of (A) figure. A sectional view of a plane is shown. It is explanatory drawing of the manufacture late stage of the conventional plate glass shaping | molding apparatus, (A) is a top view, (B) is sectional drawing of the XX plane of (A) figure, (C) is YY of (A) figure. A sectional view of a plane is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Molded body 1a, 10a Glass supply groove 1b, 10b Overflow weir 1c, 10c Both side wall outer surface 1d, 10d Lower end 1e, 10e Both side wall top ridge line 1f, 10f Both side wall guide 1g, 10g Molten glass center area 1h, 10h Molten glass Both end regions 10n Through hole 2, 20 Molten glass supply pipe 3, 30 Support refractory 40, 40a, 40b, 40c, 40d Support member 41 Cavity part 42 Groove part G Molten glass F Gravity P Plate glass Pα Central part of plate glass Pβ Periphery of plate glass Part

Claims (7)

It has a bowl-shaped molten glass supply groove with an open top at the top, the top of both side walls of the glass supply groove is used as an overflow weir, and the outer surface of both side walls has a substantially wedge-shaped cross section at the outer surface of both side walls. It is provided with a molded body that is made to approach each other downward and terminated at the lower end, inserted into a through-hole inside the molded body with a support member, held at both ends of the support member by a holding table, and molten glass is made of glass A sheet glass forming apparatus that continuously supplies from one end of the supply groove to overflow from both side wall top ridge lines, flows down along the outer surface of both side walls, and joins at a substantially wedge-shaped lower end to form a sheet glass,
A flat glass molding apparatus, wherein the support member is in the shape of a long bar, and the section modulus of the bar section is in the range of 1 × 10 ⁻⁶ to 8 × 10 ⁻³ m ³ .   2. The sheet glass forming apparatus according to claim 1, wherein the support member has a structure having a hollow portion.   2. The sheet glass forming apparatus according to claim 1, wherein the support member has a structure having a recess and / or a groove.   The support member for a sheet glass forming apparatus, wherein the unevenness of the surface roughness of the outer surface is 5 mm or less, and is mounted on the sheet glass forming apparatus according to claim 1.   The support member for a sheet glass forming apparatus according to claim 4, wherein the ratio of the Young's modulus of the support member to the Young's modulus of the constituent material constituting the molded body is in the range of 1 to 10. Using the sheet glass forming apparatus according to claims 1 to 3, in a temperature environment of 1000 ° C. or higher, the sheet thickness dimension is 3 mm or less, the width dimension is 1500 mm or more, and the density is 2.9 g / A method for forming a plate glass, comprising forming a plate glass of cm ³ or less.   7. The method for forming a sheet glass according to claim 6, wherein the sheet glass for mounting a liquid crystal display device is continuously formed by a downward stretch forming means.

Images