JP6485169B2 - Manufacturing method of glass material - Google Patents

Description

  The present invention relates to a method for producing a glass material.

  In recent years, research on a containerless floating method has been made as a method for producing a glass material. For example, in Patent Document 1, a barium titanium ferroelectric sample suspended in a gas floating furnace is irradiated with a laser beam, heated and melted, and then cooled to cool the barium titanium ferroelectric sample to glass. Is described. In the conventional method of melting glass using a container, crystals may precipitate when the molten glass comes into contact with the wall surface of the container, but in the containerless floating method, crystals caused by contact with the wall surface of the container The progress of conversion can be suppressed. For this reason, even a material that could not be vitrified by a conventional manufacturing method using a container may be vitrified by a containerless floating method. Therefore, the containerless floating method is a method that should be noted as a method capable of producing a glass material having a novel composition.

JP 2006-248801 A

  The problem of the containerless floating method is to improve the homogeneity of the glass material. Therefore, in Patent Document 1, a plurality of lasers are used to irradiate a wide area of a glass raw material lump with a laser. However, even in this method, crystals are likely to precipitate due to contact between the glass melt and the mold, and it is difficult to obtain a sufficiently homogeneous glass.

  A main object of the present invention is to provide a method capable of producing a glass material having excellent homogeneity by a containerless floating method.

  In the method for producing a glass material according to the present invention, a glass raw material lump is suspended in a state where the glass raw material lump is suspended above the molding surface by ejecting gas from a gas ejection hole opened on the molding surface of the mold. After the molten glass is heated and melted by irradiating the laser beam to obtain molten glass, the molten glass is cooled to obtain a glass material, and the flow rate of the gas from the gas ejection hole after the glass raw material lump is melted Is made smaller than the flow rate of the gas from the gas ejection holes before the glass raw material lump is melted. By doing in this way, the glass raw material lump and the molten glass obtained by melting the glass raw material lump can be stably suspended, and the contact between the glass raw material lump and the molten glass and the mold can be suppressed. A glass material with excellent homogeneity can thus be produced.

  In the method for producing a glass material according to the present invention, it is preferable to reduce the flow rate of the gas from the gas ejection holes before the glass raw material lump is completely melted. In this case, it can suppress that a molten glass contacts a shaping | molding die and a crystal nucleus etc. produce | generate in a molten glass.

  In the method for producing a glass material according to the present invention, it is preferable to increase the flow rate of the gas from the gas ejection hole after stopping the irradiation of the laser beam. By doing so, the glass material can be stably suspended in the cooling step.

  ADVANTAGE OF THE INVENTION According to this invention, the method which can manufacture the glass material which has the outstanding homogeneity by the containerless floating method can be provided.

It is typical sectional drawing of the manufacturing apparatus of the glass material which concerns on 1st Embodiment. It is a schematic plan view of a part of the molding surface in the first embodiment. It is a time chart of the gas flow rate in a 1st embodiment. It is typical sectional drawing of the manufacturing apparatus of the glass material which concerns on 2nd Embodiment. It is a time chart of the gas flow rate in a 3rd embodiment.

  Hereinafter, the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

(First embodiment)
In the present embodiment, not only a normal glass material, but also a glass material having a composition that does not vitrify by a melting method using a container, for example, that does not include a network-forming oxide can be suitably manufactured. Specifically, for example, barium titanate glass material, lanthanum-niobium composite oxide glass material, lanthanum-niobium-aluminum composite oxide glass material, lanthanum-niobium-tantalum composite oxide glass material, lanthanum- A tungsten composite oxide glass material or the like can be suitably produced.

  FIG. 1 is a schematic cross-sectional view of a glass material manufacturing apparatus 1 according to the first embodiment. As shown in FIG. 1, the glass material manufacturing apparatus 1 includes a mold 10. The molding die 10 includes a curved molding surface 10a. Specifically, the molding surface 10a has a spherical shape.

  The molding die 10 has a gas ejection hole 10b opened in the molding surface 10a. As shown in FIG. 2, in this embodiment, a plurality of gas ejection holes 10b are provided. Specifically, the plurality of gas ejection holes 10b are arranged radially from the center of the molding surface 10a.

  In addition, the shaping | molding die 10 may be comprised with the porous body which has an open cell. In that case, the gas ejection hole 10b is constituted by continuous bubbles.

  The gas ejection hole 10b is connected to a gas supply mechanism 11 such as a gas cylinder. Gas is supplied from the gas supply mechanism 11 to the molding surface 10a via the gas ejection hole 10b. A gas flow rate adjustment unit 11a is provided between the gas supply mechanism 11 and the gas ejection hole 10b. The flow rate of the gas ejected from the gas ejection hole 10b can be controlled by the gas flow rate adjusting unit 11a. The gas flow rate adjusting unit 11a can be configured by, for example, a valve or the like.

  The type of gas is not particularly limited. The gas may be, for example, air or oxygen, or an inert gas such as nitrogen gas, argon gas, or helium gas.

  When manufacturing a glass material using the manufacturing apparatus 1, first, the glass raw material lump 12 is arrange | positioned on the molding surface 10a. The glass raw material lump 12 may be, for example, a glass material raw material powder integrated by press molding or the like. The glass raw material lump 12 may be a sintered body that is sintered after integrating the raw material powder of the glass material by press molding or the like. Moreover, the glass raw material lump 12 may be an aggregate of crystals having a composition equivalent to the target glass composition.

  The shape of the glass raw material lump 12 is not particularly limited. The glass raw material block 12 may be, for example, a lens shape, a spherical shape, a cylindrical shape, a polygonal column shape, a rectangular parallelepiped shape, an elliptical shape, or the like.

  Next, the glass raw material block 12 is floated on the molding surface 10a by ejecting gas from the gas ejection holes 10b. That is, the glass raw material block 12 is held in the air in a state where the glass raw material block 12 is not in contact with the molding surface 10a. In this state, the glass material block 12 is irradiated with laser light from the laser irradiation device 13. Thereby, the glass raw material lump 12 is heated and melted to be vitrified to obtain molten glass. Thereafter, the glass material can be obtained by cooling the molten glass. In the step of heating and melting the glass raw material lump 12 and the step of cooling until the temperature of the molten glass and further the glass material becomes at least the softening point or less, at least gas ejection is continued, and the glass raw material lump 12, molten glass or glass It is preferable to suppress contact between the material and the molding surface 10a. In the following description, the step of irradiating the glass raw material lump 12 or the melt of the glass raw material lump 12 with laser light is referred to as a “melting step”. Therefore, in the melting step, the step of starting the irradiation of the laser beam to the glass raw material block 12, the step of irradiating the glass raw material block 12 with the laser light and melting the glass raw material block 12, and the melting of the glass raw material block 12 are performed. And a step of homogenizing the molten glass obtained by irradiating the molten glass with a laser beam.

  As a result of intensive studies, the present inventors have found that the floating state of the glass raw material block 12 and the molten glass changes when the gas flow rate is made constant in the melting step. Specifically, for example, when the gas flow rate is set so that the glass raw material lump 12 floats stably, the gas flow rate is too large, and thus the molten glass vibrates excessively or fluctuates. May be easy to touch. On the other hand, if the gas flow rate is set so that the molten glass floats stably, the gas flow rate is too small, and the glass raw material mass 12 may not be sufficiently floated. If the glass raw material lump 12 is not sufficiently floated, a part of the glass raw material lump 12 that is partially melted may come into contact with the mold 10 and become a starting point for crystallization. Moreover, since the position of the glass raw material lump 12 is difficult to change, a specific part is easily heated locally, and composition shift due to evaporation of the glass component may occur.

  In the present embodiment, the gas flow rate from the gas ejection hole 10b after the glass raw material mass 12 is melted by the gas flow rate adjusting unit 11a is set to the gas flow rate from the gas ejection hole 10b before the glass raw material mass 12 is melted. Less than. Therefore, both the glass raw material lump 12 and the molten glass obtained by melting the glass raw material lump 12 can be floated suitably. Thereby, it can suppress that the glass raw material lump 12 and molten glass contact the shaping | molding die 10. FIG.

  Specifically, in the present embodiment, as shown in FIG. 3, before starting the melting step, the gas flow rate ejected to the glass raw material block 12 is set to L1. The gas flow rate ejected to the molten glass after the glass raw material mass 12 is completely melted is L2 lower than L1. Thereafter, the ejection of gas from the gas ejection holes 10b is stopped. By doing in this way, it can suppress that a crystal | crystallization and a crystal nucleus arise in molten glass. Therefore, a homogeneous glass material can be manufactured.

  It is preferable to reduce the gas flow rate from L1 to L2 until the glass raw material mass 12 is completely melted. After the glass raw material mass 12 starts to melt, the glass raw material mass 12 is completely melted and the molten glass and It is preferable to reduce the flow rate of the gas from L1 to L2 in the period up to. By doing so, it can suppress more effectively that a molten glass contacts the shaping | molding die 10. FIG.

  From the viewpoint of obtaining a more homogeneous glass material, L1 / L2 is preferably 1.05 to 1.5, and more preferably 1.1 to 1.2. Note that L1 and L2 can be appropriately set depending on, for example, the shape and size of the glass raw material block 12 and the shape of the gas ejection hole 10b. L1 and L2 are, for example, about 0.5 L / min to 15 L / min. It can be.

  Hereinafter, other examples of preferred embodiments of the present invention will be described. In the following description, members having substantially the same functions as those of the first embodiment are referred to by the same reference numerals, and description thereof is omitted.

(Second Embodiment)
FIG. 4 is a schematic cross-sectional view of the glass material manufacturing apparatus 1a according to the second embodiment.

  In the first embodiment, the example in which the plurality of gas ejection holes 10b are opened on the molding surface 10a has been described. However, the present invention is not limited to this configuration. For example, one gas ejection hole 10b opened at the center of the molding surface 10a may be provided like the glass material manufacturing apparatus 1a shown in FIG.

(Third embodiment)
FIG. 5 is a time chart of the gas flow rate in the third embodiment. As shown in FIG. 5, in this embodiment, after stopping the irradiation of the laser term, the flow rate of the gas from the gas ejection hole 10b is increased in the cooling process. Specifically, after stopping the irradiation of the laser term, in the cooling step, the gas flow rate L2 in the melting step is increased from the gas flow rate L3 to a flow rate L3 larger than the flow rate L2. By doing in this way, the formed glass material can be stably floated in a cooling process. For example, if the gas flow rate is kept at the flow rate L2 even in the cooling step, the formed glass material may not float stably. This is because the glass material formed by cooling has a higher density than the molten glass lump, and it is less likely to float due to its small surface area and small area exposed to gas. It is done. The flow rate L3 / flow rate L2 is preferably 1.05 to 1.5, and more preferably 1.1 to 1.2. Specifically, the flow rate L3 varies depending on the shape and the like of the glass raw material block 12, but is preferably about 1 L / min to 15 L / min, for example.

  The flow rate L3 is more preferably less than the flow rate L1. The glass raw material block 12 is usually porous or distorted in shape, whereas the formed glass material is solid and has a well-shaped shape. This is because the flow rate of the gas can be small. Specifically, the flow rate L3 / flow rate L1 is preferably 0.98 or less, and more preferably 0.95 or less.

DESCRIPTION OF SYMBOLS 1,1a Manufacturing apparatus 10 Mold 10a Molding surface 10b Gas ejection hole 11 Gas supply mechanism 11a Gas flow volume adjustment part 12 Glass raw material lump 13 Laser irradiation apparatus

Claims (5)

The glass raw material lump is heated by irradiating the glass raw material lump with a laser beam in a state where the glass raw material lump is suspended and held above the forming surface by jetting gas from a gas ejection hole opened on the molding surface of the mold. After obtaining molten glass by melting, including a step of obtaining a glass material by cooling the molten glass,
By reducing the flow rate of the gas from the gas ejection hole from the start of melting of the glass raw material mass until it completely melts,
The flow rate of the gas from the gas ejection holes after the glass raw material mass was completely melted, the glass raw material mass to less than the flow rate of the gas from the gas ejection hole before starting the melting of the glass material Production method. The method for producing a glass material according to claim 1, wherein the flow rate of the gas from the gas ejection hole is increased after the irradiation of the laser beam is stopped. When the flow rate of gas from the gas ejection hole before the glass raw material mass starts melting is L1, and the flow rate of gas from the gas ejection hole after the glass raw material mass is completely melted is L2. L1 / L2 is in the range of 1.05-1.5, The manufacturing method of the glass material of Claim 1 or 2. The flow rate of the gas from the gas jet hole in the cooling step of the molten glass after stopping the irradiation of the laser light is set to L2 after the gas raw material block is completely melted. The manufacturing method of the glass material of any one of Claims 1-3 which has L3 / L2 in the range of 1.05-1.5, when L3 is set to L3. The flow rate of the gas from the gas ejection hole in the cooling step of the molten glass after stopping the irradiation of the laser beam is set to L1 before the melting of the glass raw material lump is started. The manufacturing method of the glass material of any one of Claims 1-4 whose L3 is less than L1, when making into L3.