JP4821260B2 - Liquid crystal plate glass heating apparatus, liquid crystal plate glass furnace, and liquid crystal plate glass manufacturing method - Google Patents

Description

  The present invention is provided with a heating device and a heating device for heating the molten glass flowing down through the molded body when the liquid crystal plate glass, that is, the plate glass used for manufacturing the panel of the liquid crystal display is formed. The present invention also relates to a manufacturing method of liquid crystal plate glass using the furnace and the heating device.

  In recent years, with the widespread use of various flat panel displays, in particular, the spread of liquid crystal displays, for example, a large amount of thin liquid crystal plate glass having a thickness of about 0.3 to 1.2 mm has been produced. This liquid crystal plate glass is actually formed by various methods typified by the overflow down draw method and the slot down draw method, but the plate glass obtained by the forming has a small surface undulation and roughness. In addition, the surface quality is required to be excellent.

  For example, in the overflow downdraw method described above, molten glass is continuously supplied to an overflow tank formed on the upper part of a substantially wedge-shaped cross section, and the molten glass is allowed to overflow from the overflow tank so that both sides of the molded body After flowing down along the side wall surface of the sheet, it is fused at the lower top part of the molded body to form a single sheet, and the sheet-shaped glass molded body in this form is cooled by the cooling rollers (edge rollers). This is a method of obtaining a liquid crystal plate glass to be the final product by pulling it downward while being pinched by a pulling roller at the stage where it is pinched and solidified (see, for example, Patent Documents 1 and 2).

  According to this type of molding method, since the molten glass in the vicinity of the molded body is not yet solidified, it has properties as a viscous fluid, and therefore the molten glass is affected by the temperature in the vicinity of the molded body. It is easy to receive. In particular, if the temperature distribution in the width direction (longitudinal direction of the overflow groove) is not uniform in the vicinity of the molded body, a portion having a different viscous force occurs in the width direction of the molten glass, and the response of the molten glass to the tensile in the width direction. There will be a difference. As a result, segregation (referred to as uneven thickness) occurs in the thickness of the plate glass in the width direction, and when this uneven thickness is large, the glass substrate is bonded to the liquid crystal glass substrate and the color filter glass substrate. As a result, a misalignment occurs, resulting in a positional shift of the alignment mark and a decrease in the yield of the liquid crystal device. As a specific example, in a manufacturing process of a TFT liquid crystal display, a pattern shift of 3 to 15 μm is caused, and display unevenness due to a decrease in luminance occurs.

  Furthermore, if the temperature distribution in the width direction in the vicinity of the molded body is not uniform in this way, stress (strain) segregation of the sheet glass occurs in the width direction, and if this stress segregation is large, cracks or the like occur in the sheet glass. This may lead to fatal defects in quality. In addition, plate glass with large stress segregation is stretched locally again when heated or cooled locally in the assembly process of the liquid crystal display. In addition to adverse effects, there is a risk of causing cracks.

  In addition, with the recent increase in the size of liquid crystal plate glass, the width direction dimension has become longer (for example, about 2000 mm), so the width direction of the molten glass has to be longer. However, under such circumstances, the importance of temperature control in the width direction is higher than in the past.

  On the other hand, for example, in the slot down draw method described above, a slit-like opening is formed in the bottom wall of the molten glass storage tank to which the molten glass is supplied, and the molten glass is caused to flow down through this opening to form a single plate. This is a method in which a pulling roller pulls out the plate-like glass molded body in this form (see, for example, Patent Document 3). Also in this slot down draw method, the importance of temperature control in the width direction is high as in the above-described overflow down draw method.

  As a technique related to temperature control as described above, according to the above-mentioned Patent Document 1, the internal space (furnace chamber) of the furnace including molding and slow cooling is divided into a plurality of chambers in the vertical direction by partition walls. A configuration is disclosed in which the room temperature is controlled by a room temperature control device for each separated room. In this furnace chamber, in order to execute the overflow down draw method, a molded body that causes the molten glass to overflow and flow down, and a tension roller that pulls out the plate-like glass molded body that is directly below the molten glass are disposed. The above room temperature control device is configured to adjust the average cooling rate from the glass transition point to the strain point of the glass during molding or slow cooling to 1.2 ° C./second.

  Further, according to the above-described Patent Document 2, a plurality of heaters are arranged adjacent to each other in the width direction in the vicinity of the molten glass in the internal space of the molding furnace, and each heater is provided for each predetermined section in the width direction. A configuration for adjusting the temperature distribution is disclosed. Furthermore, according to the above-mentioned Patent Document 3, a plurality of heating not only in the width direction but also in the up-down direction are provided in the vicinity of the plate-like glass formed in the interior space of the slow cooling furnace immediately below the molten glass. It is disclosed that an appropriate slow cooling temperature condition is obtained by arranging a vessel and adjusting the temperature distribution in the vertical direction.

Japanese Patent Laid-Open No. 10-53426 JP 2001-31434 A JP 2001-31435 A

  By the way, the temperature control method disclosed in the above-mentioned Patent Document 1 can only adjust the atmospheric temperature for each chamber formed by dividing the furnace chamber into a plurality of chambers, that is, the temperature can be adjusted with one chamber as one unit. Therefore, the temperature control is performed in such a manner that the entire temperature of one chamber is substantially the same, and therefore the temperature is different stepwise for different chambers. For this reason, if the volume of each chamber is large, it is extremely difficult to precisely control the temperature in the furnace chamber. On the other hand, if the volume of each chamber is reduced, the number of chambers increases unreasonably, The temperature control between them becomes complicated, and the construction time in the furnace becomes longer, the cost of the furnace rises, and the maintenance becomes difficult. In this temperature control method, since the furnace chamber is separated in the vertical direction by the partition wall, it is natural that the temperature distribution in the width direction cannot be adjusted, but it is assumed that the furnace chamber is separated in the width direction. However, the same problem as described above occurs.

  On the other hand, the temperature control methods disclosed in Patent Documents 2 and 3 have a plurality of heaters arranged adjacent to each other in the width direction. However, considering the recent increase in the size of the liquid crystal plate glass, And the problem of stress segregation cannot be solved. That is, for example, a heater provided with a linear heating element (heat generating element wire) that is frequently used for this type of application will be described. As shown in FIG. The heating element wires 17a are bent and attached to the back plate 17b so as to have a wave shape in which the heating wires 17a are arranged in a plurality of rows at a constant pitch P. In other words, the heating element wires 17a are arranged with a constant distribution density in the width direction (the left-right direction in the figure). In addition, as this kind of heater 17, it is usual to use the dimension of the width direction about 150-500 mm, Preferably about 300-400 mm.

  In this state, the temperature distribution of the heater 17 in which the heating element wires 17a are arranged is inevitably higher at the center than at the widthwise end of the heater 17, as shown by the characteristic curve B in FIG. Therefore, when a plurality of heaters 17 are arranged adjacent to each other in the width direction as described above, the center portion in the width direction of each heater 17 is schematically shown in FIG. 9 as its characteristic curve BX. A high temperature peak F1 is formed, and a low temperature valley H1 is formed between the end portions of the heaters 17 in the width direction. In addition, these trough parts H1 become still lower temperature for the reason on construction, when each heater 17 must be installed at fixed intervals (about 3-5 mm) mutually. .

  If the single heater 17 having such characteristics is arranged in the vicinity of the molded body with the width direction of the heater 17 and the width direction of the molten glass being matched, the heating temperature for the molten glass is It is impossible to make uniform the temperature distribution in the width direction of the molten glass to the extent that problems such as uneven thickness of the liquid crystal plate glass can be surely avoided because it is unfairly different between the central portion and both end portions. I must say. Further, even if a plurality of heaters 17 having such characteristics are arranged adjacent to each other in the width direction in order to cope with an increase in the size of the liquid crystal plate glass, the total temperature due to the assembly of these heaters 17 is reduced. Since the distribution is unreasonably large in temperature difference between the plurality of peak portions F1 and valley portions H1 as in the characteristic curve BX shown in FIG. 9 above, it is natural that this also in the width direction of the molten glass. It becomes extremely difficult to make the temperature distribution uniform. As a result, as shown in FIG. 10, uneven thickness portions Z1 that can be fatal defects are generated at a plurality of locations corresponding to each other between the heaters 17 in the width direction of the liquid crystal plate glass GX. If the heater 17 is reduced in size and the number of the heaters 17 is increased, the temperature distribution of the molten glass in the width direction can be made uniform to some extent. However, in such a case, not only a large number of control circuits are required, but the temperature control of each heater is complicated, the construction time in the furnace is prolonged, the cost of the furnace is increased, and further This causes a difficulty in maintenance and the like, and substantially the same fatal problem as when the furnace chamber is separated into a plurality of parts as described above occurs.

  Further, as disclosed in Patent Document 3, after the molten glass flowing down from the molded body becomes a sheet glass molded body, the above-described sheet glass molded body is subjected to a slow cooling treatment in a slow cooling furnace. Even if a plurality of heaters 17 are arranged, the heating temperature distribution of one heater is not appropriate as described above, so that slow cooling conditions (heating conditions) that can produce liquid crystal plate glass with little warpage and small residual strain It is extremely difficult to obtain a temperature distribution that exactly matches (1).

The present invention has been made in view of the above circumstances, and by making improvements so that the heating temperature distribution of a single heater is suitable, the temperature distribution in the width direction of the molten glass is effectively uniformized. possible to avoid problems such as uneven thickness of the liquid crystal plate glass Te shall be the challenge the.

The present invention, which has been made to solve the above problems, is to form liquid crystal sheet glass through the lower opening of the furnace while the molten glass led to the molded body existing in the upper part of the furnace flows down and is formed into a plate shape. A heating apparatus for a liquid crystal plate glass used for subjecting a molten glass to a heat treatment in the process until being drawn, wherein the temperature in the width direction of the molten glass is adjusted by adjusting a heating temperature in at least the width direction of the molten glass. In order to make the distribution uniform, linear heating elements provided in a single heater are arranged in parallel, and a plurality of linear portions extending continuously over the entire vertical length of the arrangement region are formed at both ends. folded wave shape bent comprising and characterized Dzu in conjunction with the presence of density in arrangement density in the width direction of the plurality of linear portions, it is provided with a plurality of the heater It is. Here, the width direction of the molten glass and the width direction of the heater are the same direction (hereinafter the same).

According to such a configuration, when the molten glass supplied to the molded body flows down, a linear heating element (hereinafter also simply referred to as a heating element) provided in a single heater is arranged in the width direction. If the installation density , specifically, the arrangement density in the width direction of the plurality of linear portions of the heating element is constant as in the prior art, even if the heating temperature for the molten glass varies unreasonably in the width direction. According to the present invention, since the density in the width direction of the heating elements provided in the single heater exists, the density of the heating elements is determined according to the density of the heating elements. Due to the temperature adjustment function of the vessel itself, it is possible to absorb the variation in the heating temperature for the molten glass. As a result, it is possible to make the heating temperature in the width direction of the molten glass more uniform than in the past, and in the past, the above-mentioned heating temperature has caused unreasonable variation in the width direction, resulting in uneven thickness and stress segregation of the liquid crystal plate glass. Is suppressed, and a high-quality liquid crystal plate glass can be obtained. Moreover, in light of the current situation that a single heater has become large (the width direction dimension is 300 mm or more) with the increase in the size of liquid crystal plate glass in recent years, a heater in the case where a plurality of heaters are arranged. From the viewpoint of reducing the number of heaters and simplifying temperature control for individual heaters, it is significant to make the arrangement density in the width direction of the heating elements provided in a single heater dense. The heater is preferably provided at a position where the molten glass can be heated, that is, in the vicinity of the molded body, but may be provided in the vicinity of the edge roller slightly below.
Furthermore, in this configuration, from the viewpoint that the temperature distribution in the width direction of the molten glass is made uniform by suppressing the temperature change in the region corresponding to each other between the plurality of heaters. with the presence of density in arrangement density in the width direction of the plurality of linear portions of the linear heating element provided on a single heater may be provided with a plurality of the heater.

In this case, arrangement density in the width direction of the plurality of linear portions of the linear heating element, that is configured to be dense in the heater in the width direction central portion in the rough and made and widthwise end portions preferable. In this way, if the arrangement density in the width direction of the heating elements provided in a single heater is constant as in the prior art, the central portion in the width direction of the heater will be hot and the end in the width direction will be even if the temperature becomes low, so that uniform the high temperature part and the low temperature portion, so that the density is present in the arrangement density of the heating element. That is, the temperature distribution in the width direction of the molten glass can be made uniform by an appropriate temperature adjustment function of the single heater itself. Therefore, the suppression of uneven thickness and stress segregation of the liquid crystal plate glass and the improvement of the quality of the liquid crystal plate glass are further ensured, and the liquid crystal plate glass can be dealt with more reliably.

  Furthermore, in order to more reliably suppress variations in the temperature distribution of the molten glass and the sheet-like glass molded body, the heating temperature of the heater is set so that the heating element has a maximum temperature at a dense part and a minimum temperature at a rough part. The difference from the temperature is preferably less than 15 ° C, more preferably less than 10 ° C.

Also, as in the above-described structure, slow cooling process for obtaining warpage and residual strain is reduced plate glass by Rukoto adjusting the heating temperature in at least the vertical direction before Symbol sheet glass molded body is subjected, it is preferable that the provided several multiple heaters of the presence Rutotomoni its a density in arrangement density in the vertical direction of the heat generating member provided in a single second heater. Here, the up-down direction of the molten glass and the up-down direction of the second heater are the same direction (hereinafter the same).

According to such a structure, when the molten glass supplied to the molded body flows down to form a plate-like glass molded body and moves downward, the heating element provided in the single second heater If the arrangement density in the vertical direction is constant as in the prior art, even if the heating temperature conditions for performing the slow cooling treatment on the sheet glass molded body cannot be precisely adjusted in the vertical direction, the present invention According to the above, since there is a density in the arrangement density of the heating elements provided in the single second heater in the vertical direction, the density of the heating elements is determined by the density of the arrangement of the heating elements . By the temperature adjustment function of the heater 2 itself, precise adjustment in the vertical direction of the heating temperature condition for the plate-like glass molded body can be performed. Therefore, it is possible to adjust the slow cooling conditions in the vertical direction of the plate-like glass molded body more precisely than before, which is advantageous not only for obtaining a liquid crystal plate glass with reduced warpage and residual strain, but also for a plurality of When the second heater is arranged, simplification of temperature control for the individual second heaters and the like can be achieved. In addition, this 2nd heater is arrange | positioned in the site | part from an edge roller to a tension roller.

In this case, depending on the ambient temperature atmosphere, etc., the arrangement density of the heating elements is such that the upper part of the second heater is dense and the lower part is rough, or the upper part is rough and the lower part is dense. It is preferable that it is comprised. In this way, if the arrangement density in the vertical direction of the heating elements provided in the single second heater is constant as in the prior art, the sheet glass molded body is subjected to a slow cooling treatment. Even when the heating temperature condition cannot be precisely adjusted in the vertical direction, the arrangement density of the heating elements exists so as to avoid such a problem. That is, the above-mentioned precise adjustment can be performed by an appropriate temperature adjustment function of the single second heater itself, and the reduction of the warp and residual strain of the liquid crystal plate glass is further ensured.

In this case, in order to obtain the above advantages more reliably, the material of the linear heating element, Kanthal alloy, nickel-chromium alloy, is preferably molybdenum or silicon carbide.

  Furthermore, in order to appropriately cope with an increase in the size of the liquid crystal plate glass, it is preferable that a plurality of heaters having the above-described configuration be arranged adjacent to each other in at least the width direction of the molten glass or the plate-like glass molded body.

  In the above configuration, it is preferable that the heating element is fixed to the heat-resistant back plate in order to efficiently heat the heater by removing harmful effects caused by heat.

  And the heating apparatus for liquid crystal plate glass provided with the above structure can be provided as a furnace for liquid crystal plate glass by arrange | positioning inside a furnace wall.

  Moreover, the manufacturing method of the liquid crystal plate glass which shape | molds plate glass by the overflow down draw method can be provided using the heating apparatus for liquid crystal plate glasses provided with the above structure. In this case, it is not excluded to form the plate glass by the slot down draw method using the heating apparatus for liquid crystal plate glass having the above-described configuration.

According to the present invention as described above, since the density is present in the arrangement density in the width direction of the plurality of linear portions of the linear heating element provided in a single heater, the linear heating element It is possible to achieve uniformity by absorbing variations in the heating temperature in the width direction of the molten glass by adjusting the density of the linear portions , that is, by the temperature adjustment function of the single heater itself. As a result, the uneven thickness and stress segregation of the liquid crystal plate glass due to the unreasonable variation in the heating temperature in the width direction are suppressed, and a high-quality liquid crystal plate glass can be obtained.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a schematic longitudinal side view schematically showing an internal state of a molding apparatus provided with a heating apparatus for liquid crystal plate glass according to an embodiment of the present invention, and FIG. 2 schematically shows the internal state of the molding apparatus. FIG. As shown in each of these drawings, the basic configuration of the molding apparatus 1 is that a molded body 2 having a substantially wedge-shaped cross section and having an overflow groove 2a formed on the upper portion, and overflowing from the upper portion of the molded body 2. A pulling roller 3 that pulls out the molten glass Y as a plate-like glass molded body G, and a cooling roller (edge roller) 4 arranged in the middle of the glass forming path from the lower top 2b of the molded body 2 to the pulling roller 3 I have. Each of these components 2, 3, 4, Y, and G is surrounded by a furnace 5 made of refractory bricks.

  And in the vicinity of the molded body 2 on the inner surface of the furnace 5, that is, on the upper inner surfaces of the side walls 5 a constituting the furnace 5, so as to face both side wall surfaces 2 c (molten glass Y) of the molded body 2, respectively. A first heating device 6 is provided. Further, between the cooling roller 4 and the pulling roller 3 on the inner surface of the furnace 5, that is, on the lower inner surfaces of both side walls 5 a constituting the furnace 5, the second glass surfaces G are respectively faced. A two-heating device 8 is provided. The first heating device 6 includes a total of eight first heaters 7 arranged in the width direction and adjacent to the upper and lower two stages for each side wall 5a and the second heating. The apparatus 8 includes three second heaters 9 arranged adjacent to each other in the width direction for each side wall 5a.

  Therefore, according to this shaping | molding apparatus 1, the molten glass Y supplied to the shaping | molding body 2 and flows down along the side wall surface 2c from the upper part is heated by the 1st heating apparatus 6, and a shaping | molding body is adjusted. 2 is fused to form a single plate, and the glass sheet G is heated by the second heating device 8 and gradually cooled, and is sandwiched by the pulling roller 3 and pulled downward. Go.

In this case, as shown in FIG. 3, in the first heater 7 which is a component of the first heating device 6, the arrangement density of the linear heating elements (heating element wires) 7a is not uniform but is dense and dense. The state is rough at the center in the width direction, and dense at both ends in the width direction. More specifically, the heating wire 7a is a plurality of linear portions 7a1 extending continuously over the vertically entire length of the sequence regions sequenced and the heating wire 7a in parallel, the wave shape formed by folding both ends In a bent state, it is fixed to the heat-resistant back plate 7b with a distance of several millimeters, and the interval (pitch) between the straight portions 7a1 of the heating element wire 7a is widened in the center region C in the width direction and each end region. N is narrower. Further, the distance between the side portions C2 of the central region C in the width direction is relatively wider than the central portion C1. Specifically, in the heating element wire 7a, the interval between the straight portions 7a1 in the central portion C1 of the widthwise central region C is 18 mm, the interval between the straight portions 7a1 in both side portions C2 is 23 mm, and the straight lines in the width direction both end regions D The interval between the portions 7a1 is 16 mm, and the distance E from the both ends to both ends of the heat-resistant back plate 7b is 14 mm. The central region C of the heating element wire 7a occupies 1/2 to 1/3 of the entire region.

  In this case, the heating element wire 7a is formed of Kanthal alloy, nickel chrome alloy, molybdenum, or silicon carbide, and this heat generation is performed in order to prevent dust generated from the heating element wire 7a from adhering to the molten glass Y. The strand 7a is covered with a ceramic refractory that does not generate dust. Further, the heat-resistant back plate 7b is formed of a material that is durable to a temperature suitable for molding the molten glass Y (for example, 1500 ° C., further 1600 ° C.) and has a property of reflecting heat rays. The shape is not limited to a rectangle, and may be a triangle, a polygon, a circle, an ellipse, or a combination thereof.

  As can be seen from the characteristic curve A shown in FIG. 4, the heating temperature distribution by the single heater 7 having such a configuration is flat with the region F from the center in the width direction to the periphery of both sides almost unchanged. On the other hand, as the region H at both ends in the width direction shifts to both sides, the temperature gradually decreases slightly. When this is compared with the characteristic curve B shown by the conventional heater 17 (the arrangement density of the heating element wires 17a is constant in the width direction), the high temperature peak portion disappears and the flat portion F becomes longer and gradually. In addition, the region H in which the temperature decreases is narrowed, the maximum temperature is decreased, and the minimum temperature is increased. As a whole, the amount of change in temperature is 1/2 or less, or 1/3 or less. In addition, the difference between the maximum heating temperature and the minimum heating temperature of the heater 7 is 8 ° C. in this embodiment, and in the case of the conventional heater 17, the temperature difference is 22 ° C.

And the heating temperature distribution by the 1st heating apparatus 6 provided with the heater 7 which shows such a characteristic in total, and arrange | positioning these 4 pieces by the upper and lower two steps | paragraphs at a width direction, ie, the width | variety of the molten glass Y As can be understood from the characteristic curve AX indicated by the solid line in FIG. 5, the high-temperature peak corresponding to the central region C in the width direction of each heater 7 becomes a relatively low-temperature flat portion F. And the temperature fall of the low-temperature valley part H corresponding between the mutual gap | intervals of each heater 7 becomes moderate. Even if the arrangement state of the heating element wires 7a in the heater 7 is changed or not changed, a characteristic curve shown by a dotted line in FIG. In addition, the flat part F may become a low temperature as a whole, and the valley part H may become a peak part. If it is the above characteristics, the temperature distribution in the width direction of the molten glass Y heated by this heating device 6 is made uniform, and each liquid crystal plate glass GX obtained as shown in FIG. The uneven thickness portion Z corresponding to the portion between the containers 7 hardly appears (FIG. 6 shows the uneven thickness portion Z exaggerated). Therefore, the temperature change which existed in the area | region corresponding between the some heaters conventionally as shown in FIG. 9 is suppressed.

On the other hand, the plate-like glass shaped material G became plate form after the molten glass Y is passed through the cooling roller 4 flows down is subjected to slow cooling process is heated by the second pressurizing heat device 8. As shown in FIG. 7, the second heater 9 which is a component of the second heating device 8 is in a state in which the arrangement density of the linear heating elements (heating element wires) 9a is dense in the vertical direction. The upper part is dense and the lower part is rough. More specifically, the heating element wires 9a are spaced apart from the heat-resistant back plate 9b by several millimeters in a state where a plurality of straight portions 9a1 arranged in parallel and extending in the width direction are bent at both ends. The distance between the straight portions 9a1 of the heating element wire 9a is gradually increased as it moves from the upper portion to the lower portion. Note that the second heater 9 has a linear heating element (heating element wire, contrary to the above, if the emphasis is on preventing an undue temperature drop when the sheet-like glass molded body G moves downward. The arrangement density of 9a may be such that the upper part is rough and the lower part is dense. In this case, the materials or characteristics of the heating element wire 9a and the heat-resistant back plate 9b are the same as those of the first heater 7 described above.

  The heating temperature distribution by the second heating device 8 in which three heaters 9 are arranged adjacent to each other in the width direction, that is, the heating temperature distribution with respect to the sheet glass molded body G is such that the sheet glass molded body G is from below to above. The temperature condition gradually changes with the shift to. Therefore, it is possible to subject the plate-like glass molded body G to a slow cooling process while adjusting the temperature near the strain point from the glass transition point by finely adjusting the temperature in the vertical direction. A high-quality liquid crystal plate glass with reduced residual strain can be obtained.

  In the above embodiment, the linear heating elements are used as the heating elements of the first heater 7 and the second heater 9, but the heating elements that can withstand the high temperatures already described are not linear. In the case of a linear heating element, the arrangement state does not need to be the state illustrated above, and other arrangement states may be used as long as the arrangement density of the linear heating elements is equal. It may be.

  Furthermore, although the said embodiment applied this invention to the liquid crystal plate glass shape | molded by the overflow downdraw method, in addition to this, this invention is applied similarly to the liquid crystal plate glass shape | molded, for example by the slot down draw method. be able to.

It is a schematic vertical side view which shows the shaping | molding apparatus by which the heating apparatus for liquid crystal plate glass which concerns on embodiment of this invention was arrange | positioned. It is a general | schematic longitudinal cross-sectional front view of the said shaping | molding apparatus. It is a front view which shows the 1st heater which is a component of the said heating apparatus for liquid crystal plate glass. It is a graph which shows the temperature characteristic of a said 1st heater. It is a graph which shows the temperature characteristic of the 1st heating apparatus comprised by the said 1st heater. It is a top view which exaggerates and shows the liquid crystal plate glass manufactured using the said 1st heating apparatus. It is a front view which shows the 2nd heater which is a component of the said heating apparatus for liquid crystal plate glass. It is a front view which shows the conventional heater. It is a graph which shows the temperature characteristic of the heating apparatus comprised with the conventional heater. It is a top view which shows the liquid crystal plate glass manufactured using the conventional heating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molding apparatus 2 Molded body 5 Furnace 5a Side wall (furnace wall) of a furnace
6 1st heating device (heating device for liquid crystal plate glass)
7 First heater 7a Heating element wire (linear heating element)
7b Heat-resistant back plate 8 Second heating device (heating device for liquid crystal plate glass)
9 Second heater 9a Heating element wire (linear heating element)
9b Heat-resistant back plate Y Molten glass G Sheet glass molded body

Claims (9)

When the liquid crystal plate glass is formed, the molten glass led to the molded body existing in the upper part of the furnace flows down and is formed into a plate shape, and then the molten glass is subjected to heat treatment until it is pulled out through the lower opening of the furnace. A heating device for liquid crystal plate glass used for applying,
The temperature distribution in the width direction of the molten glass is made uniform by adjusting the heating temperature in at least the width direction of the molten glass,
A linear heating element provided in a single heater is bent into a wave shape in which a plurality of linear portions arranged in parallel and continuously extending over the entire vertical length of the arrangement region are folded at both ends. and with the presence of density in arrangement density in the width direction of the plurality of linear portions, the liquid crystal plate glass heating apparatus characterized in that it comprises a plurality of the heater. Linear heat generation provided in the single heater so that the temperature distribution in the width direction of the molten glass is made uniform by suppressing the temperature change in the corresponding region between the plurality of heaters. the arrangement density in the width direction of the plurality of linear portions of the body together with the density exists, the liquid crystal sheet glass heating apparatus according to claim 1, characterized in that the heater is provided plural. Arrangement density in the width direction of the plurality of linear portions of the wire-like heating element is characterized by being configured so as to be dense in the heater in the width direction central portion in the rough and made and widthwise end portions The heating apparatus for liquid crystal plate glass according to claim 1 or 2. The heating temperature of the heater is such that a difference between a maximum temperature of a portion where the linear heating element is dense and a minimum temperature of a portion where the linear heating element is coarse is less than 15 ° C. A heating apparatus for liquid crystal plate glass according to any one of the above.   In a single second heater, a slow cooling process is performed to obtain a plate glass with reduced warpage and residual strain by adjusting the heating temperature in at least the vertical direction of the plate-like glass molded body. The heating apparatus for liquid crystal plate glass according to any one of claims 1 to 4, wherein the heating element provided is provided with a plurality of heaters while the arrangement density of the heating elements in the vertical direction is made dense. The heating device for liquid crystal plate glass according to any one of claims 1 to 5, wherein a material of the linear heating element is Kanthal alloy, nickel chromium alloy, molybdenum or silicon carbide. The said linear heating element is being fixed to the heat resistant back plate, The heating apparatus for liquid crystal plate glass in any one of Claims 1-6 characterized by the above-mentioned. A furnace for liquid crystal plate glass, wherein the heating device for liquid crystal plate glass according to any one of claims 1 to 7 is disposed inside a furnace wall. Using a liquid crystal sheet glass heating apparatus according to any one of claims 1 to 7, a method of manufacturing a liquid crystal panel glass, which comprises forming a sheet glass by an overflow down-draw method.

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