JP5449281B2 - Manufacturing method of glass strip - Google Patents

Description

  The present invention relates to a glass strip manufacturing method for manufacturing a thin rod-shaped glass strip by heating and stretching a thick-plate base glass plate.

  Conventionally, it is most important to improve the flatness and surface roughness of glass plates used for semiconductor element substrates, spacers used in field effect flat panel displays, magnetic disk substrates, and the like. However, in the float method and molding method generally used as the present glass plate manufacturing method, when manufacturing a thin glass plate, the flatness of the resulting glass plate is poor. To finish, a considerable amount of the surface of the glass plate had to be ground and polished. For this reason, the glass plate after grinding has the problem that the surface roughness will become very bad.

  In order to solve this problem, it is common to polish the glass plate after grinding twice, and the surface roughness is about 0.5 nm after the primary polishing and about 0.1 nm after the secondary polishing. Yes. Furthermore, since the next generation is required to have higher accuracy, it is expected that a third polish will be required in addition to this. Therefore, if it is attempted to increase the flatness of the glass plate only by searching / polishing, it takes time and labor for grinding / polishing, resulting in equipment costs.

  Therefore, a thin glass plate having a desired thickness is obtained by heating and softening a base glass plate having a predetermined thickness and improved surface roughness, and then stretching the softened glass plate. Has been devised (see Patent Document 1).

  In addition, in such a method for producing a glass sheet, a configuration in which a plurality of cooling means are arranged along the width direction of the plate is used, and the power of the heater at the corresponding position is adjusted with respect to the uneven thickness of the local thickness of the glass sheet. Alternatively, a means for eliminating local uneven thickness is disclosed by partially cooling the width direction (see Patent Document 2).

Japanese Patent Application Laid-Open No. 11-199255 JP-A-8-183627

  However, for example, when a base glass plate is heated and softened and stretched to form a thin glass strip having a thickness of 0.7 mm or less, it is difficult to make the thickness of the glass strip uniform in the width direction. The glass strip after stretching was inferior in flatness.

  The present invention has been made in view of the above, and when the base glass plate is heated and softened in a heating furnace and stretched to a desired thickness to form a glass strip, the flatness of the base glass plate is improved. It aims at providing the manufacturing method of the glass strip which can manufacture the excellent thin rod-shaped glass strip.

  In order to solve the above-described problems and achieve the object, the glass strip manufacturing method according to the present invention heats and softens the base glass plate in a heating furnace, and stretches the glass strip to a desired thickness. The heating and stretching step includes the step of starting the melting of the base material glass plate to the position of the inflection point in the contour line of the base material glass plate formed during the stretching. Is heated so that the length becomes 2/3 or more of the width of the base glass plate.

  Moreover, in the manufacturing method of the glass strip according to the present invention, in the above invention, the heating and stretching step is performed from the position at which the base glass plate starts melting from the base glass plate formed during the stretching. It heats so that the length to the position of the inflection point in an outline may be 1.5 times or less of the width | variety of the said base material glass plate.

  Moreover, the manufacturing method of the glass strip which concerns on this invention is said base material glass plate formed in the said extending | stretching process in said invention from the position at which the said heat | fever extending process starts at least the melting | fusing start of the said base material glass plate. Heating is performed so as to have a concave temperature distribution in the width direction in a portion up to the position of the inflection point in the contour line.

  Further, in the method for producing a glass strip according to the present invention, in the above invention, in the heating and stretching step, a viscosity ratio between a center portion and an end portion in the width direction of the base glass plate is greater than 1 and 20 or less. It heats so that it may become.

  Further, in the glass strip manufacturing method according to the present invention, in the above invention, the heating and stretching step includes a non-heat generating portion at a position facing a central portion in the width direction of the base glass, It heats using the heating body which has a heat-emitting part on both sides.

  Further, in the method for producing a glass strip according to the present invention, in the above invention, the heating and stretching step is performed at least from a part at the beginning of melting of the base material glass plate to a part of a strain point temperature of the base material glass plate. It heats so that it may be contained in the said heating furnace.

The glass strip manufacturing method according to the present invention is characterized in that, in the above invention, the base glass plate having a thermal expansion coefficient of 32 × 10 ⁻⁷ (1 / k) or less is used.

  Moreover, the manufacturing method of the glass strip which concerns on this invention uses the thing which consists of borosilicate glass or quartz glass as said base material glass plate in said invention.

  The glass strip manufacturing method according to the present invention is characterized in that, in the above invention, the heating and stretching step is performed such that a cross-sectional aspect ratio of the glass strip is 50 or more.

  The glass strip manufacturing method according to the present invention is characterized in that, in the above invention, the heating and stretching step is performed such that the thickness of the glass strip is 0.7 mm or less.

  According to the present invention, in the heating and stretching step, the length from the position where the base glass plate starts to melt to the position of the inflection point in the contour line of the base glass plate formed during stretching is the base material. By heating so that it becomes 2/3 or more of the width of the glass plate, the difference in the flow rate of the glass at the center portion and the end portion of the base glass plate does not increase, so the thickness of the glass strip in the width direction is uniform. Thus, it is possible to produce a glass strip having excellent flatness.

FIG. 1 is a perspective view of a heating and stretching apparatus used in a method for producing a glass strip according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the heating furnace shown in FIG. FIG. 3 is a plan view of the heating furnace shown in FIG. FIG. 4 is a schematic diagram showing a graph showing the temperature distribution in the width direction of the base glass plate and an outline of the arrangement of heaters corresponding to the base glass plate. FIG. 5 is a schematic view of a heater in which a carbon block is installed instead of the central heater. Drawing 6 is an explanatory view explaining the manufacturing method of the glass strip concerning another embodiment of the present invention. FIG. 7 is a plan view of a heating furnace used in a glass strip manufacturing method according to still another embodiment of the present invention. FIG. 8 is a plan view of a heating furnace used in a method for manufacturing a glass strip according to still another embodiment of the present invention. FIG. 9 is a diagram illustrating Examples 1 to 5 and Comparative Example 1. 10 is a diagram showing Examples 6 to 8 and Comparative Example 2. FIG. FIG. 11 is a diagram illustrating Examples 9 to 11.

  Below, with reference to drawings, embodiment of the manufacturing method of the glass strip which concerns on this invention is described in detail. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a perspective view of a heating and stretching apparatus used in a method for producing a glass strip according to an embodiment of the present invention. The heating and stretching apparatus 50 includes a heating furnace 10 that is an electric resistance furnace for heating the base glass plate 1, a base material feeding mechanism 20 that feeds the base glass plate 1 into the heating furnace 10, and a glass strip from the heating furnace 10. 11 and a take-out mechanism 30 for pulling out 11. The heating furnace 10 is provided with a plurality of heaters (not shown) as heating means for heating the base glass plate 1. Further, at the lower part of the heating furnace 10, an outer shape measuring device 7 for measuring the outer shape of the glass strip 11, a protective film coating apparatus 8 for forming a protective film on the surface of the glass strip 11, and a tension for pulling the glass strip 11 are measured. A tension measuring device 9 and a guide roll 5 for preventing the glass strip 11 from being kinked are provided. In addition, a cutter 21 is provided at the lower portion of the take-up mechanism 30 to cut a groove on the surface of the glass strip and fold it into a predetermined length. The measured value measured by the outer shape measuring instrument 7 is fed back to the base material feeding mechanism 20 via the feedback path 13. The base material feed mechanism 20 controls the base material feed speed based on this feedback value. The measured value is also fed back to the take-up mechanism 30 via the feedback path 14. The take-off mechanism 30 controls the drawing speed based on this feedback value.

  2 is a cross-sectional view of the heating furnace 10 shown in FIG. 1, and FIG. 3 is a plan view of the heating furnace 10 shown in FIG. The base glass plate 1 is disposed in a rectangular furnace core tube 17 inside the furnace body 16. A plurality of heaters 15 a, 15 b and 15 c are installed outside the core tube 17. For example, a carbon resistance heating element is used as the heater. Further, the periphery of the heater is protected with an inert gas so that the heater is not consumed.

  When the base glass plate is heated to a temperature equal to or higher than the softening point, it softens and starts to melt, its width contracts and is stretched. During stretching, the outline of the base glass plate forms an inflection point, after which a glass strip having the desired thickness and width is formed. The base glass plate is called the meniscus portion from the start of melting to the position of the inflection point, and the length of this portion is called the meniscus length. In the meniscus portion, a difference in glass flow occurs between the center portion and the end portion in the width direction of the base material glass plate.

  In the present invention, in the heating and stretching step, the base glass plate is heated so as to have a concave temperature distribution in the width direction. Then, since the temperature of the end portion of the base glass plate is higher than that of the central portion, the viscosity of the glass is further lowered, and the speed at which the glass flows is increased. In this way, in the meniscus portion of the base glass plate, the difference in the glass flow that has occurred at the center and the end in the width direction is compensated by the difference in the viscosity of the glass, and the glass flow speed Therefore, the thickness of the glass strip in the width direction becomes uniform, and a glass strip with excellent flatness can be manufactured.

  FIG. 4 is a schematic diagram showing a graph showing the temperature distribution in the width direction of the base glass plate in the heating furnace shown in FIG. 2 and an outline of the arrangement of heaters corresponding to the base glass plate. The horizontal axis of the graph indicates the temperature measurement position on the base glass plate, and the vertical axis indicates the relative temperature of the base glass plate at the measurement position. And the arrangement | positioning of the heater corresponding to a base material glass plate is shown in the lower part of a graph. By making the heater 15b at a position facing the center of the base glass plate at a lower temperature than the heaters 15a and 15c on both sides thereof, the base glass plate has a concave temperature distribution as shown in the graph in the width direction. Can be heated.

  As described above, heating the base glass plate so as to have a concave temperature distribution in the width direction may be performed by not applying power to the heater 15b at the center in FIG. As described above, a carbon block 18 may be installed instead of the heater 15b. Thus, if heating is performed using a heating body that has a non-heat generating portion at a position opposite to the central portion in the width direction of the base glass and has heat generating portions on both sides of the non-heat generating portion, the base glass The temperature difference between the center portion and the end portion of the plate can be further increased, and the viscosity of the glass can be further differentiated. Further, even if a heat insulating material having a higher thermal conductivity is used as the heat insulating material for the furnace outside the furnace core tube, this temperature difference can be further increased. As such a heat insulating material, for example, a box made of carbon blocks and packed with carbon fiber can be used. Such a heat insulating material can have a thermal conductivity of 0.4 to 4 W / mk or more.

(Embodiment 2)
Next, another embodiment of the present invention will be described. Although the above-mentioned Embodiment 1 can manufacture a glass strip with excellent flatness by defining the temperature distribution in the width direction of the base glass plate, this embodiment is based on the base glass plate. By defining the relationship between the temperature distribution in the heating furnace in the stretching direction and the width of the base glass plate, a glass strip with excellent flatness can be produced.

  Drawing 6 is an explanatory view explaining the manufacturing method of the glass strip concerning another embodiment of the present invention. According to the present embodiment, the heating and stretching step is the length from the position where the base glass plate starts to melt to the position of the inflection point in the contour line of the base glass plate formed during stretching, that is, Heating is performed so that the meniscus length 22 is 2/3 or more of the width 23 of the base glass plate. In this way, the length of the meniscus portion of the base glass plate is sufficiently long, so that the inclination gradient of the end portion accompanying shrinkage of the width of the glass plate is reduced, and the glass flow speed between the center portion and the end portion The difference between is not large. Therefore, the thickness of the glass strip in the width direction becomes uniform, and a glass strip with excellent flatness can be manufactured.

  The meniscus length 22 can be appropriately adjusted by adjusting the length of the heater and adjusting the length of the heat zone in the drawing direction of the base glass plate in the heating furnace. If the heat zone is lengthened, the meniscus length 22 can be longer. The meniscus length can also be increased by increasing the drawing speed. Here, the heat zone refers to a portion where the temperature in the heating furnace is equal to or higher than the softening point of the glass used, as shown in FIG. 6, and the heat zone in the stretching direction of the base glass plate. The length 24 is defined as the heat zone length. The base glass plate has a minimum viscosity at the portion where it reaches the maximum temperature, and its contour forms an inflection point. The position where the glass reaches the maximum temperature is determined by the combination of the heat zone and the drawing speed.

  Therefore, by adjusting the length and arrangement of the heaters 15a, 15b, and 15c as appropriate, the length from the upper end portion of the heat zone to the highest temperature portion and the heat zone length are adjusted, and the base glass plate as described above is adjusted. Heating can be performed so that the length from the melting start position to the position of the inflection point in the contour line of the base glass plate formed during stretching becomes 2/3 or more of the width of the base glass plate. In the present embodiment, the heaters 15a, 15b, and 15c may be set to the same temperature and heated so that the base glass plate has a uniform temperature distribution in the width direction. By setting the temperature lower than that of the heaters 15a and 15c, not turning on the power of the heater 15b, or installing a carbon block instead of the heater 15b, the base glass plate has a concave temperature distribution in the width direction. If the glass strip is heated to have a thickness, the thickness in the width direction of the glass strip becomes even more uniform, and a glass strip with even better flatness can be produced.

(Embodiment 3)
Next, still another embodiment of the present invention will be described. The above-described first embodiment can manufacture a glass strip having excellent flatness by defining the temperature distribution in the width direction of the base glass plate, and the second embodiment is the same as that of the base glass plate. By defining the relationship between the temperature distribution in the heating furnace in the drawing direction and the width of the base glass plate, a glass strip having excellent flatness can be produced. In the present embodiment, by combining these and further defining a position for defining the temperature distribution in the width direction, a glass strip having a more excellent flatness can be manufactured with high heating efficiency.

  FIG. 7 is a plan view of a heating furnace used in a glass strip manufacturing method according to still another embodiment of the present invention. As described above, the heating furnace 40 including the heaters 15d, 15e, and 15f having relatively short heater lengths is used, and the heaters 15d and 15f are formed at the time of stretching at least from the position where the base glass plate starts to melt. The portion up to the position of the inflection point on the contour line of the base glass plate, that is, the meniscus portion 25 is heated so as to have a concave temperature distribution in the width direction of the base glass plate. Further, by disposing the heater 15e having a relatively short heater length below the portion 25, from the position where the base glass plate starts to melt, in the contour line of the base glass plate formed at the time of stretching. It heats so that the length to the position of an inflection point may become 2/3 or more of the width | variety of a base material glass plate. In this way, even if the length of each heater is short, the thickness of the glass strip in the width direction becomes even more uniform, and a glass strip with even better flatness can be manufactured.

  That is, the position of the inflection point of the contour line of the base glass plate is the point where the viscosity of the glass is minimized in the stretching direction, and below that, the glass is cooled and solidified, so the part below the inflection point Then, even if the length of the heaters at both ends is increased to form a concave temperature distribution in the width direction, the influence on the flatness of the glass strip to be formed is relatively small. In other words, it is important to heat the base glass plate from the start of melting to the position of the inflection point of the contour line so as to have a concave temperature distribution in the width direction. A heater may be used at both ends. On the other hand, the upper part of the base glass plate and the upper part of the heat zone can be sufficiently heated by the heaters at both ends. Therefore, the central heater does not have to be long up to the upper part and is lower than the heaters at both ends. If the heater is placed at a position where the highest temperature part of the heat zone can be formed further downward, even if the heater length is relatively short, the base glass plate starts to melt Heating can be performed such that the length to the position of the inflection point in the contour line of the base glass plate formed at that time is 2/3 or more of the width of the base glass plate.

(Embodiment 4)
Next, still another embodiment of the present invention will be described. Although the above-mentioned Embodiments 1-3 can make the thickness of the width direction of a glass strip uniform, and can manufacture the glass strip excellent in flatness, this embodiment is in any of the above-mentioned embodiments. Can also be combined, whereby the glass strip does not become distorted.

  FIG. 8 is a plan view of a heating furnace used in the glass strip manufacturing method according to still another embodiment of the present invention. In this way, using the heating furnace 60 surrounded by the structure 19 that extends the lower part of the heating furnace in the heating furnace 10, from the beginning of melting of the base glass plate to the strain point temperature of the base glass plate. And heat to be contained in the heating furnace. In this way, when the glass strip is drawn out from the heating furnace to the atmosphere, there is no possibility that the glass strip is rapidly cooled to a temperature below the strain point temperature to cause strain. Moreover, the drawing speed of the glass strip can be increased. Further, if heating is performed so that a portion from the beginning of melting of the base glass plate to a portion having a temperature 50 ° C., more preferably 100 ° C. lower than the strain point temperature of the base glass plate, is included in the heating furnace, Is more preferable because it does not occur reliably.

  Below, the Example of the manufacturing method of the glass strip concerning this invention is described in detail. Note that the present invention is not limited to the embodiments.

(Examples 1-5, Comparative Example 1)
As an example of the present invention, a base glass plate made of borosilicate glass (Tempax Float (registered trademark) manufactured by Schott) or quartz and having a width of 328 mm, a thickness of 5 mm, and a length of about 1.5 m was prepared. The glass strip was manufactured by heating and stretching. As for the heating furnace, use a heater with three heaters arranged on both sides of the base glass plate as shown in FIG. 2, or use a furnace with the lower part of the furnace surrounded by a structure as shown in FIG. did. A heater having a length of 620 mm and a width of 256 mm was used, and the heaters were arranged such that the distance between the heater center lines was 277 mm. The stretching conditions were a drawing speed of 4 mm / min, a width after stretching of 25 mm, and a thickness of 0.38 mm. The cross-sectional aspect ratio at this time is 66. The cross-sectional aspect ratio is the ratio of the width and thickness in the cross section of the glass plate. In addition, when the cross-sectional aspect ratio of the glass strip is 50 or more, the thickness is 0.7 mm or less, or both, there is an effect of improving the flatness of the present invention. It becomes more prominent.

  Hereinafter, Examples 1 to 5 and Comparative Example 1 shown in FIG. 9 will be described. Example 1 is a case where the temperature of the heater at the center is set to 900 ° C. and the temperature of the heaters at both ends is set to 1010 ° C. in the heating furnace of FIG. At this time, the temperature of the central portion of the base glass plate was 915 ° C., the temperatures of both ends were 945 ° C., and a temperature difference between them was a concave temperature distribution of 30 ° C. The glass strip manufactured under such conditions had a concave lens shape in cross section, but the flatness was 5 μm with respect to the plate width of 20 mm, which was good. Flatness is the highest point in the vertical direction at two points separated by an arbitrary unit length on the substrate surface when the glass strip is cut out as a substrate of the required area and then placed on a horizontal plane. And the difference between the lowest score. In the above case, the unit length was 20 mm.

  On the other hand, Comparative Example 1 is a case where the temperature of the heaters at the center and both ends is set to the same 1000 ° C. in the heating furnace of FIG. At this time, the temperature of the central part of the base glass plate was 985 ° C., the temperatures of both ends were 980 ° C., and there was almost no temperature difference. The glass strip manufactured under such conditions had a concave lens shape with a remarkable cross section, and the flatness was as large as 40 μm with respect to a plate width of 20 mm.

  In Example 2, in the heating furnace of FIG. 2, the central heater does not turn on the power, and further, carbon fiber is packed in a box made of carbon blocks as a heat insulating material outside the furnace of the furnace core tube. I used it. The heat conductivity of this heat insulating material was 0.4 to 4 W / mk. Thus, the temperature difference between the central portion and both end portions in the width direction of the base glass plate was set to 60 ° C., which is larger than that in the case of Example 1. At this time, the ratio of the viscosity of the glass between the central portion and both end portions in the width direction of the base glass plate was 11.6. The glass strip produced under such conditions was good with a flatness of 3 μm with respect to a plate width of 20 mm.

  On the other hand, in Example 3, as in Example 2, the central heater did not apply power, and a heat insulating material having a thermal conductivity of 4 W / mk or more was used. Thus, the temperature difference between the central portion and both end portions in the width direction of the base glass plate was set to 80 ° C., which is larger than those in the first and second embodiments. At this time, the ratio of the viscosity of the glass between the central portion and both end portions in the width direction of the base glass plate was 26.3. The glass strip produced under such conditions has a flatness of 10 μm with respect to a plate width of 20 mm, which is improved as compared with Comparative Example 1, but larger than Examples 1 and 2. Furthermore, the cross-sectional area of the glass strip was convex. That is, when the temperature of the central portion of the base glass plate was lowered too much, the viscosity increased too much, and conversely the flatness tended to deteriorate. From these results, it was found that it is preferable to heat so that the viscosity ratio between the central portion and the end portion in the width direction of the base glass plate is greater than 1 and 20 or less.

Example 4 is a case where a base glass plate made of quartz is used. In the heating furnace of FIG. 2, the temperature of the heater at the center is set to 2020 ° C., and the temperatures of the heaters at both ends are set to 1780 ° C., respectively. At this time, the temperature of the central part of the base glass plate was 1790 ° C., the temperature of both ends was 1950 ° C., and a temperature difference between them was a concave temperature distribution of 160 ° C. The glass strip produced under such conditions was good with a flatness of 2 μm with respect to a plate width of 20 mm. Thus, when a base glass plate made of a material having a thermal expansion coefficient of 32 × 10 ⁻⁷ (1 / k) or less, such as Tempax Float (registered trademark) or quartz, is used, a rectangular furnace is used. Even when a temperature difference is likely to occur between the front and back surfaces of the glass plate as described above, the difference in elongation between the front surface and the back surface is small, so that bending due to thermal expansion of the glass plate hardly occurs and a flatter glass strip can be formed. Moreover, since it does not break even if it is rapidly heated and rapidly cooled, the drawing speed of the glass strip can be increased.

  Example 5 is a case where the lower part of the furnace is surrounded by an extended structure as shown in FIG. The drawing speed was 7 m / min. In this case, the structure is surrounded by 1.5 m below the heater lower end of the furnace, and the stretched glass strip can be gradually cooled until it exits the heating furnace and is rapidly cooled by the atmosphere. Thereby, it was possible to gradually cool to Tempus Float (registered trademark) strain point temperature of 510 ° C. Thus, by using the structure with the furnace bottom extended, even if the drawing speed is increased, the glass strip is not distorted, and the flatness is 5 μm with respect to the plate width of 20 mm, which is good. Met.

(Examples 6 to 8, Comparative Example 2)
As an example of the present invention, a base glass plate having a width of 328 mm, a thickness of 5 mm, and a length of about 1.5 m made of Tempax Float (registered trademark) having a softening point of 820 ° C. was prepared, and this was heated and stretched. Glass strips were manufactured. As for the heating furnace, a heater in which three heaters were arranged on both sides of the base glass plate as shown in FIG. 2 was used. The temperature of each heater was set to 1000 ° C. At this time, the temperature of the central part of the base glass plate was 985 ° C., the temperatures of both ends were 980 ° C., and there was almost no temperature difference. As drawing conditions, the drawing speed was 7 mm / min.

  Hereinafter, Examples 6 to 8 and Comparative Example 2 shown in FIG. 10 will be described. In Example 6, the heat zone length is adjusted by setting the heater length to an appropriate length, and heating is performed so that the meniscus length is 1.2 times the width of the base glass plate (base metal width). This is the case. The glass strip produced under such conditions was good with a flatness of 5 μm with respect to a plate width of 20 mm.

  On the other hand, Comparative Example 2 is a case where the meniscus length is heated so as to be 0.61 times the width of the base material. The glass strip produced under such conditions was large with a flatness of 40 μm with respect to a plate width of 20 mm.

  Example 7 is a case where the width | variety of a base material glass plate is large, Comprising: It is a case where it heats so that meniscus length may be 0.68 times of base material width | variety. The glass strip manufactured under such conditions was good with a flatness of 5 μm with respect to a plate width of 60 mm. That is, regardless of the width of the base glass plate, the length from the position where the base glass plate starts to melt to the position of the inflection point in the contour line of the base glass plate formed during stretching (meniscus length However, it has been found that glass strips with excellent flatness can be produced by heating to 2/3 or more of the width of the base glass plate.

  Example 8 is a case where the meniscus length is heated so as to be 1.5 times the width of the base material glass plate (base material width). The glass strip produced under such conditions was good with a flatness of 5 μm with respect to a plate width of 20 mm. However, in this case, the response of the shape of the glass strip to the adjustment of the manufacturing conditions becomes slow, and it may be difficult to adjust the average value of the width and thickness of the glass strip by fine adjustment of the drawing speed. . From this result, the length (meniscus length) from the position where the base glass plate starts to melt to the position of the inflection point in the contour line of the base glass plate formed during stretching is as follows. It was found that a glass strip whose width and thickness were accurately controlled could be produced by heating so that the width was 1.5 times or less.

(Examples 9 to 11)
As an example of the present invention, a base glass plate having a width of 328 mm, a thickness of 5 mm, and a length of about 1.5 m made of Tempax Float (registered trademark) was prepared, and this was heated and stretched to produce a glass strip. . As for the heating furnace, use one having three heaters arranged on both sides of the base glass plate as shown in FIG. 2, or one using a heater having a relatively short heater length as shown in FIG. did. All heaters were 256 mm wide. The stretching conditions were a drawing speed of 7 mm / min, a width after stretching of 25 mm, and a thickness of 0.38 mm. The cross-sectional aspect ratio at this time is 66.

  Hereinafter, Examples 9 to 11 shown in FIG. 11 will be described. In Example 9, in the heating furnace of FIG. 2, the temperature of the heater at the center is set to 875 ° C., the temperature of the heater at both ends is set to 1055 ° C., and the length of the heater is set to an appropriate length. This is a case where the heat zone length is adjusted and heating is performed so that the meniscus length becomes 0.88 times the width of the base glass plate (base metal width). At this time, the temperature of the central part of the base glass plate was 920 ° C., the temperature of both ends was 980 ° C., and a temperature difference between these was a concave temperature distribution of 60 ° C. The glass strip produced under such conditions was very good with a flatness of 1 μm for a plate width of 20 mm.

  In the heating furnace of FIG. 2, the temperature of the heater at the center is set to 875 ° C., and the temperatures of the heaters at both ends are set to 1055 ° C., respectively. And it is a case where it heats so that meniscus length may be 0.61 time of base material width | variety. The glass strip manufactured under such conditions had a flatness of 3 μm with respect to a plate width of 20 mm, which was good, but was slightly larger than the value of Example 9. That is, the inflection point in the contour line of the base glass plate formed during stretching so that the base glass plate has a concave temperature distribution in the width direction and from the start of melting of the base glass plate It was found that glass strips with even better flatness can be produced by heating so that the length to the position (meniscus length) is 2/3 or more of the width of the base glass plate.

  Example 11 is a case where heating is performed in a heating furnace using a heater having a relatively short heater length as shown in FIG. In this case, by performing the same temperature setting as in Example 9, the temperature difference between the central portion and both end portions of the base glass plate was a concave temperature distribution of 60 ° C. Further, although the heater length is about ½ of that in the ninth embodiment, the heat zone length can be the same as that in the ninth embodiment, and the meniscus length can be set to 0. 0 of the base material width as in the ninth embodiment. It became 88 times. The glass strip produced under such conditions was very good, as in Example 9, with a flatness of 1 μm with respect to a plate width of 20 mm. In addition, since a heater having a short heater length is used, heating can be performed efficiently with a small amount of electric power.

  As described above, the glass strip produced by the method for producing a glass strip according to the present invention can be developed into a group of products utilizing its flatness and surface properties. For example, it is useful for spacers and circuit board materials used in semiconductor elements, field effect flat panel displays, and particularly suitable for semiconductor element substrates, spacers used in field effect flat panel displays, and small magnetic disk substrates. It is a thing.

  When quartz glass is used, a functional film can be deposited on the surface by thermal CVD or the like using its high temperature resistance. Further, when multi-component glass is used, a functional film can be deposited on the surface using a low temperature process.

  Furthermore, the glass strip of the present invention may be cut into a polygonal shape, a circular shape, or a disk shape and used as a glass substrate in accordance with the intended use, and the obtained substrate may be polished and used. The glass substrate produced using the glass strip of the present invention is also suitable for a glass substrate of a DNA chip used for medical analysis or the like. Further, the glass strips of the present invention can be extended to a two-dimensional substrate of any size by arranging them in a plane.

DESCRIPTION OF SYMBOLS 1 Base material glass plate 5 Guide roll 7 Outline measuring device 8 Protective film coating apparatus 9 Tension measuring device 10, 40, 60 Heating furnace 11 Glass strip 13, 14 Feedback path 15a-15f Heater 16 Furnace body 17 Core tube 18 Carbon block 19 Structure 20 Base material feed mechanism 21 Cutter 22 Meniscus length 23 Base material glass plate width 24 Heat zone length 25 Meniscus portion 30 Take-up mechanism 50 Heating and stretching device

Claims (9)

A heating and stretching step in which the base material glass plate is heated and softened in a heating furnace and stretched to a desired thickness to form a glass strip, and the heating and stretching step is a position at which the base material glass plate starts to melt From the heating up so that the length to the position of the inflection point in the contour line of the base glass plate formed during the stretching is 2/3 or more of the width of the base glass plate , The glass strip is stretched so that the cross-sectional aspect ratio of the glass strip is 50 or more .   In the heating and stretching step, the length of the base glass from the position where the base glass plate starts to melt to the position of the inflection point in the contour line of the base glass plate formed during the stretching is the base glass. The method for producing a glass strip according to claim 1, wherein heating is performed so that the width of the plate is 1.5 times or less.   The heating and stretching step is concave in the width direction at least in a portion from a position at which the base glass plate starts to melt to a position of the inflection point in the contour line of the base glass plate formed during the stretching. The method for producing a glass strip according to claim 1, wherein the glass strip is heated so as to have a temperature distribution.   4. The glass strip according to claim 3, wherein in the heating and stretching step, heating is performed so that a viscosity ratio between a central portion and an end portion in the width direction of the base glass plate is greater than 1 and 20 or less. Manufacturing method.   The heating and stretching step is characterized in that heating is performed using a heating body having a non-heat generating portion at a position opposite to a central portion in the width direction of the base glass, and having a heat generating portion on both sides of the non-heat generating portion. The manufacturing method of the glass strip of Claim 3 or Claim 4.   The heating and drawing step is characterized in that heating is performed so that at least a portion from the melting start temperature of the base glass plate to a strain point temperature portion of the base glass plate is included in the heating furnace. The method for producing a glass strip according to any one of claims 1 to 5. The glass ^{strip according} to any one of claims 1 to 6, wherein the base glass plate has a thermal expansion coefficient of 32 x ^10-7 (1 / k) or less. Method.   The method for producing a glass strip according to claim 7, wherein the base glass plate is made of borosilicate glass or quartz glass. The method for producing a glass strip according to any one of claims 1 to 8 , wherein the heating and stretching step is performed such that the thickness of the glass strip is 0.7 mm or less.

Images