KR101806791B1 - Manufacturing method of quartz glass ingot with large area - Google Patents

Manufacturing method of quartz glass ingot with large area Download PDF

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Publication number
KR101806791B1
KR101806791B1 KR1020150124607A KR20150124607A KR101806791B1 KR 101806791 B1 KR101806791 B1 KR 101806791B1 KR 1020150124607 A KR1020150124607 A KR 1020150124607A KR 20150124607 A KR20150124607 A KR 20150124607A KR 101806791 B1 KR101806791 B1 KR 101806791B1
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KR
South Korea
Prior art keywords
quartz glass
glass ingot
mold
chamber
quartz
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KR1020150124607A
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Korean (ko)
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KR20170027960A (en
Inventor
김유진
김형준
유리
윤지연
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한국세라믹기술원
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B20/00—Processes specially adapted for the production of quartz or fused silica articles, not otherwise provided for
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/02—Pure silica glass, e.g. pure fused quartz
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/02—Pure silica glass, e.g. pure fused quartz
    • C03B2201/03—Impurity concentration specified
    • C03B2201/04—Hydroxyl ion (OH)
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B2201/00—Type of glass produced
    • C03B2201/06—Doped silica-based glasses
    • C03B2201/07—Impurity concentration specified
    • C03B2201/075—Hydroxyl ion (OH)

Abstract

A method for manufacturing a quartz glass ingot, comprising the steps of: placing a plurality of quartz glass ingots as a starting material and quartz powder having a melting point lower than that of the quartz glass ingot as a starting material in a mold; charging a mold containing the quartz powder and a plurality of the quartz glass ingots into the chamber And heating and maintaining the temperature in the chamber to a temperature in the range of 1700 to 1900 ° C so that the quartz powder and the plurality of quartz glass ingots are melted And cooling the quartz powder and the plurality of quartz glass ingots after melting the quartz glass ingot, and cooling the quartz glass ingot. According to the present invention, it is possible to manufacture a large-area quartz glass ingot having a size-up of the quartz glass ingot and a small birefringence and excellent mechanical properties.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quartz glass ingot,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a quartz glass ingot, and more particularly, to a large-area quartz glass ingot having a size-up of a quartz glass ingot and a small birefringence.

BACKGROUND ART Quartz glass is mainly used for products such as lenses, reticles, and liquid crystal displays. Recently, studies for obtaining a quartz glass having a large area in accordance with the trend of enlargement have been made.

It is necessary to form the quartz glass ingot so as to have a large area for use as an optical member having a large area or the like.

However, there is a limit in manufacturing a quartz glass ingot having a large area.

The present invention proposes a method for size-up such that a pre-formed quartz glass ingot has a large area.

Korean Patent Registration No. 10-1287275

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a large-area quartz glass ingot having a size-up of a quartz glass ingot and a small birefringence.

A method for manufacturing a quartz glass ingot, comprising the steps of: placing a plurality of quartz glass ingots as a starting material and quartz powder having a melting point lower than that of the quartz glass ingot as a starting material in a mold; charging a mold containing the quartz powder and a plurality of the quartz glass ingots into the chamber And heating and maintaining the temperature in the chamber to a temperature in the range of 1700 to 1900 ° C so that the quartz powder and the plurality of quartz glass ingots are melted And a step of cooling the quartz powder and the plurality of quartz glass ingots after they are melted, thereby producing a large area quartz glass ingot.

The plurality of the quartz glass ingots preferably have an OH group concentration in the range of 10 to 2,000 ppm.

The quartz powder is preferably added to the mold in an amount of 0.001 to 2 parts by weight based on 100 parts by weight of the total amount of the quartz glass ingot used as a starting material.

The quartz powder preferably has a lower thermal expansion coefficient than a plurality of quartz glass ingots used as a starting material.

The quartz powder preferably has a lower OH group concentration than the quartz glass ingot used as a starting material.

The quartz powder preferably has an average particle diameter of 100 nm to 500 m.

It is preferable that the quartz powder is dried in an oven to remove moisture and used as a starting material before use as a starting material.

The method for manufacturing the large area quartz glass ingot includes the steps of: forming the chamber, the mold placed in the chamber and acting as a self heating source, and a heating unit for heating the mold by a high frequency induction heating method, A gas supply unit for supplying an inert gas to the chamber; an exhaust apparatus for reducing the pressure in the chamber to a vacuum state under atmospheric pressure to evacuate the chamber; and a gas outlet for discharging the gas in the chamber Whereby a large-area quartz glass ingot can be produced.

The inert gas may be a gas containing helium (He), argon (Ar) or nitrogen (N 2 ) gas, and the inert gas may be supplied at a flow rate of 1 to 20 slpm.

The inner wall, which is a portion of the quartz glass ingot used as a starting material, which is in contact with the molten material, is made of DLC (diamond like carbon) or tungsten carbide (WC), and the outer wall is made of a graphite material It is preferable to use a mold.

It is preferable that a mold containing a plurality of quartz glass ingots is covered with a cover and sealed. The inside portion, which is a portion in contact with the molten material of the quartz glass ingot used as a starting material, is made of DLC (diamond like carbon) or tungsten carbide And the outer portion is preferably made of a graphite material so as to serve as a self heating source.

It is preferable to maintain the temperature at 1700 to 1900 占 폚 for 30 to 120 minutes.

It is preferable that the cooling is gradual cooling in the range of 0.1 to 10 占 폚 / min.

According to the present invention, it is possible to manufacture a large-area quartz glass ingot having a size-up of the quartz glass ingot and a small birefringence and excellent mechanical properties. It is possible to manufacture a large-area quartz glass ingot having a small size and a small birefringence so that a pre-formed quartz glass ingot has a large area without changing optical or mechanical properties.

When a plurality of quartz glass ingots are joined while being melted, voids (voids) may occur between the faces and the faces, or trapped bubbles may occur between the faces and the faces. The quartz powder is melted faster than the quartz glass ingot because it has a lower melting point than the quartz glass ingot used as the starting material. The melted quartz powder not only binds different quartz glass ingots, It is possible to prevent voids from being formed in the large-area quartz glass ingot finally formed. Further, since the OH group concentration of the quartz powder is low, the generation of trap bubbles due to volatilization can be prevented, and the number of trap bubbles can be reduced.

Since the outer wall of the mold is made of a graphite material, it is advantageous that the mold itself can act as a heating source while being heated by a heating means for heating by a high frequency induction heating method.

CO, CO 2, or SiC gas may be generated when the inner wall of the mold, which is made of graphite material and is in direct contact with the molten material, is made of a graphite material. The generated SiC can adhere to the surface of the quartz glass ingot, There is a problem that a compressive stress is applied to the quartz glass surface due to the difference in thermal expansion coefficient between the quartz glass and the graphite when cooling, but cracks may be generated. However, the inner side wall of the mold is made of diamond like carbon (DLC), tungsten carbide WC), it can suppress this phenomenon. Since the inner side wall of the mold is made of a material such as DLC (diamond like carbon) or tungsten carbide (WC), impurities can be prevented from being mixed in the molten material and reaction between the molten material and the graphite can be prevented. The difference in heat shrinkage during cooling due to the difference in coefficient of linear expansion between the mold and the mold is reduced and the stress that the mold compresses the large-area quartz glass ingot during cooling can be reduced.

If inert gas is injected during cooling, generation of reaction products is suppressed to obtain a large-area quartz glass ingot having high purity, and the cooling rate can be controlled.

1 is a view showing an apparatus for manufacturing a large-area quartz glass ingot according to a preferred embodiment of the present invention.
2 is a cross-sectional view illustrating a mold for manufacturing a large-area quartz glass ingot according to a preferred embodiment of the present invention.
3 is a plan view showing a state in which a plurality of quartz glass ingots are arranged in a mold.
4 is a sectional view showing the mold lid.
5 is a cross-sectional view showing the mold covered with the mold cover.
6 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1750 ° C for 1 hour according to Experimental Example 1. FIG.
7 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1800 ° C for 1 hour according to Experimental Example 1. FIG.
8 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1750 ° C for 1 hour according to Experimental Example 2. FIG.
FIG. 9 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1,800 ° C. for 1 hour according to Experimental Example 2. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it should be understood that the following embodiments are provided so that those skilled in the art will be able to fully understand the present invention, and that various modifications may be made without departing from the scope of the present invention. It is not. Wherein like reference numerals refer to like elements throughout.

Hereinafter, the quartz glass ingot is used as a starting raw material and means that it is before the size-up, and the large-area quartz glass ingot has a larger area than the quartz glass ingot used as the starting raw material It is used as meaning after size-up.

The present invention proposes a method of manufacturing a large-area quartz glass ingot having a small birefringence while being formed by size-up of a quartz glass ingot.

A method of manufacturing a large area quartz glass ingot according to a preferred embodiment of the present invention includes the steps of arranging a plurality of quartz glass ingots as a starting material and a quartz powder having a melting point lower than that of the quartz glass ingot in a mold, Filling the chamber with a mold containing the quartz glass ingot, reducing the pressure in the chamber to less than atmospheric pressure to bring the chamber into a vacuum state, heating and maintaining the chamber to a temperature in the range of 1700 to 1900 ° C Thereby melting the quartz powder and the plurality of quartz glass ingots, and cooling the quartz powder and the plurality of quartz glass ingots to melt.

Hereinafter, a method of manufacturing a large-area quartz glass ingot according to a preferred embodiment of the present invention will be described in more detail.

1 is a view showing an apparatus for manufacturing a large-area quartz glass ingot according to a preferred embodiment of the present invention. 2 is a cross-sectional view illustrating a mold for manufacturing a large-area quartz glass ingot according to a preferred embodiment of the present invention. 3 is a plan view showing a state in which a plurality of quartz glass ingots are arranged in a mold. 4 is a sectional view showing the mold lid. 5 is a cross-sectional view showing the mold covered with the mold cover.

1 to 5, the mold 120 is provided with a chamber 110 for providing a space in which the mold 120 is loaded, a mold 120 placed in the chamber 110, A heating unit 130 for heating the inside of the chamber 110, a gas supply unit 140 for supplying an inert gas to the chamber 110, and a gas supply unit 140 for reducing the pressure in the chamber 110 to a vacuum state An exhaust device 150, and a gas outlet 160 for discharging the gas in the chamber 110.

Preferably, the chamber 110 is made of a heat-resistant material that is chemically stable and has a melting point higher than the melting temperature of the quartz glass ingot. The chamber 110 is provided with a heating means 130. The heating means 130 is powered by a power supply means (not shown) to control the temperature in the chamber 110. The chamber 110 may be surrounded by a thermal insulator (not shown). The outer wall of the chamber 110 serves to heat the heat heated by the heating means 130 and to suppress the heat loss to the maximum. The outer wall of the chamber 110 may be made of a ceramic material such as a refractory material, a ceramic fiber board, a ceramic blanket, It is preferable that it is made of a material having a material heat shielding effect.

A gas inlet 170 for introducing an inert gas is connected to the chamber 110 and a gas inlet 170 is connected to the gas supply unit 140 to supply the inert gas to the chamber 110 . A gas supply part 140 for providing an inert gas is disposed outside the chamber 110 and an inert gas is introduced into the chamber 110 through the gas inlet 170.

The gas exhaust port 160 is connected to the chamber 110 and the gas exhaust port 160 may be provided with an exhaust device 150 such as a pump. The pressure (or degree of vacuum) in the chamber 110 can be adjusted by the exhaust device 150. An inert gas (or a purge gas) may be used to purge the impurity gas present in the chamber 110 and exhaust the gas through the gas outlet 160. When the quartz glass ingot is cooled, the inert gas remaining in the chamber 110 may be poured through the gas inlet 170 to cool the quartz glass ingot, and then exhausted through the gas outlet 160. The exhaust apparatus 150 includes a vacuum pump for evacuating the chamber 110 or exhausting gas therein, a valve (not shown) for shutting off or regulating the exhaust of the gas by the vacuum pump, And the like.

The mold 120 is loaded into the chamber 110 and can itself serve as a heating source for the synthesis of the material. The outer wall 124 of the mold 120 may itself be made of a graphite material having a high melting point to serve as a heating source. The mold 120 has a generally cylindrical structure, but is not limited thereto and may be manufactured in various shapes as desired.

The mold 120 may include an outer wall 124 made of graphite and an inner wall 122 therein. The inner wall 122 of the mold 120 that is in direct contact with the molten material has a high surface strength and can withstand the melting temperature of the quartz glass ingot and does not generate impurities even when brought into contact with the molten material, It is preferable to use a material such as diamond like carbon (DLC) or tungsten carbide (WC). Since the inner wall 122 of the mold 120 is made of a material such as DLC (diamond like carbon) or tungsten carbide (WC), impurities can be prevented from being mixed with the molten material and the molten material and the graphite of the mold 120 The difference in heat shrinkage during cooling caused by the difference in coefficient of linear expansion between the quartz glass ingot and the mold 120 is reduced and the stress caused by the mold 120 compressing the large-area quartz glass ingot during cooling .

The mold 120 may be supported by the pedestal 126 and may be provided so as to be separated from the left and right in order to facilitate demoulding of the large-area quartz glass ingot finally produced.

The heating means 130 is disposed around the chamber 110 and serves to heat and melt the quartz glass ingot in the mold 120. The heating temperature by the heating means 130 is appropriately selected in consideration of the physical properties and characteristics of the quartz glass ingot. In the mold 120, the plurality of quartz glass ingots 180 are heated to an appropriate temperature and melted.

The temperature inside the chamber 110 heated by the heating means 130 is preferably a temperature at which the quartz glass ingot 180 can be sufficiently melted. The temperature inside the chamber 110 is adjusted according to the type of the quartz glass ingot 180 to be melted and the heating means 130 can control the temperature according to the characteristics of the quartz glass ingot 180 I have.

The heating means 130 serves to melt the plurality of quartz glass ingots 180 by heating the mold 120 to raise the temperature in the chamber 110 to a predetermined value or higher and maintaining the temperature at a target temperature. The heating means 130 raises the temperature of the mold 120 (or the internal temperature of the chamber 110) to a target temperature (for example, 1700 to 1900 ° C) and keeps the temperature constant. The heating means 130 may be a high frequency induction heating method or the like. The temperature in the chamber 110 can be kept constant by the heating means 130. [

When the heating means 130 uses a radio frequency (RF) induction heating method, the RF coil may be arranged to surround the chamber 110. The RF coil is connected to a high frequency generator, and high frequency power generated from the high frequency generator is applied through the RF coil. The mold 120 through the RF coil can be heated to a desired temperature. When the high frequency induction heating method is used, the temperature of the mold 120 can be set to a high temperature (for example, 1700 to 1900 ° C).

A cover 190 for sealing the upper portion of the mold 120 may be further provided. The inner side portion 192 of the lid, which is in contact with the molten metal, is preferably made of a material such as diamond like carbon (DLC) or tungsten carbide (WC). The outer portion 194 of the lid is preferably made of a graphite material to serve as a self heating source.

Hereinafter, a method of manufacturing a large-area quartz glass ingot using the above-described apparatus will be described.

A plurality of quartz glass ingots 180 are prepared for size-up (or large area). The quartz glass ingot 180 may be a lump of quartz glass which is mainly composed of SiO 2 or may be a synthetic quartz glass ingot to which a component for changing the refractive index such as Ge, Ti, B, F, and Al is added. Commercialized quartz glass ingots sold on the market can be purchased and used as a starting material for size-up. The quartz glass ingot 180 preferably has a low OH group concentration, for example, an OH group concentration of 2,000 ppm or less (for example, about 10 to 2,000 ppm). The OH group concentration of less than 10 ppm is preferable because the OH group concentration is about 10 to 2,000 ppm because the production is difficult and the price is high. If a quartz glass ingot 180 having a high OH group concentration is used, there may be a problem that the refractive index is changed. The OH group contained in the quartz glass ingot 180 may cause degradation of the refractive index characteristics of the large-area quartz glass ingot which is finally formed by breaking the mesh structure of the SiO 2 tetrahedron.

Further, a quartz powder (quartz powder or fused silica powder) having a lower melting point than the plurality of quartz glass ingots (180) used as a starting material is prepared. The quartz powder is preferably an amorphous powder mainly composed of SiO 2 and having a thermal expansion coefficient (for example, 10 -6 / ° C) lower than that of the plurality of quartz glass ingots 180 used as a starting material. The quartz powder preferably has an average particle diameter of about 100 nm to 500 m. When the thickness of the quartz glass ingot 180 is greater than 500 탆, it is difficult for the quartz glass ingot 180 to rapidly flow into the interface or void between the quartz glass ingots 180 while being melted. Accordingly, Which is not effective in reducing the number of trapped bubbles occurring at the interface or voids between the electrodes. It is preferable that the quartz powder has a lower OH group concentration than the quartz glass ingot 180 used as a starting material, for example, the OH group concentration is 1,500 ppm or less (for example, about 1 to 1,500 ppm). It is preferable that such quartz powder is dried in an oven to remove moisture before use as a starting material. The drying is preferably carried out at a temperature of about 80 to 200 DEG C for 10 minutes to 48 hours.

A plurality of quartz glass ingots (180) and quartz powder are placed in the mold. It is preferable that the quartz powder is uniformly distributed in the mold 120 and the plurality of quartz glass ingots 180 are disposed adjacent to each other. The quartz powder is preferably added in an amount of 0.001 to 2 parts by weight based on 100 parts by weight of the total amount of the quartz glass ingot 180 used as a starting material. The inner shape of the mold 120 can be formed into a desired shape of the large-area quartz glass ingot that is finally produced. The inner shape of the mold 120 may be a cylindrical shape as shown in FIG. 1, a square column, May be formed in a polygonal shape. The quartz powder and the plurality of quartz glass ingots 180 may be accommodated in the mold 120 and then the upper portion of the mold 120 may be covered with the lid 190 to be sealed. The inner side portion 192 of the lid 190 which is a portion in contact with the molten glass (molten glass) formed by melting the quartz glass ingot 180 is also preferably made of a material such as DLC (diamond like carbon) or tungsten carbide (WC) .

A mold 120 containing quartz powder and a plurality of quartz glass ingots 180 is charged into the chamber 110.

The pressure in the chamber 110 is reduced to less than atmospheric pressure (e.g., 2 to 3 x 10 < -2 > Torr) using the exhaust device 150 to make the vacuum state.

The temperature in the chamber 110 is raised to a temperature in the range of 1700 to 1900 ° C and held for a predetermined time so that the plurality of quartz glass ingots 180 are melted. The temperature rise is preferably performed at a rate of about 1 to 20 占 폚 / min.

When the temperature reaches 1700 to 1900 ° C, the inside of the quartz glass ingot 180 is sufficiently heated and melted (for example, 30 to 120 minutes). If the temperature is lower than 1700 ° C, the quartz glass ingot 180 may not be sufficiently melted. If the temperature exceeds 1900 ° C, the viscosity of the molten glass drastically decreases and irregularities may occur on the surface of the large-area quartz glass ingot finally formed. If the temperature is higher than 1900 ° C, a large amount of CO, CO 2 , SiO, or SiC gas may be generated due to the reaction between the graphite and the molten glass, and bubbles may be generated in the large-area quartz glass ingot And the birefringence can be increased. In consideration of these points, the heating temperature is set to a temperature of 1700 to 1900 ° C.

When the temperature is maintained at 1700 to 1900 ° C, the plurality of quartz glass ingots 180 are melted and the molten material flows into the mold 120 according to the inner shape of the mold 120.

When the plurality of quartz glass ingots 180 are melted and joined together, voids (voids) may be generated between the surfaces and a trapped bubble may occur between the surfaces and the surfaces. The quartz powder has a lower melting point than the quartz glass ingot 180 used as a starting material and melts faster than the quartz glass ingot 180 at the holding temperature (for example, 1700 to 1900 ° C), and the melted quartz powder is different Not only serves to bind the quartz glass ingot 180 but also serves to fill the voids between the quartz glass ingots 180 and to prevent voids from being formed in the finally produced large area quartz glass ingot can do. Further, since the OH group concentration of the quartz powder is low, the generation of trap bubbles due to volatilization can be prevented, and the number of trap bubbles can be reduced.

The retention time is preferably about 30 to 120 minutes at a temperature of 1700 to 1900 DEG C and less than 30 minutes if the quartz glass ingot 180 is not sufficiently melted. Excessive bubbles may be generated in the inside of the large-area quartz glass ingot, excessive amounts of impurities may be contained, and the purity may be lowered.

On the other hand, the inner wall 122 of the mold 120 which is in direct contact with the molten material has a high surface strength, can withstand the melting temperature of the quartz glass ingot, does not generate impurities even when brought into contact with the molten glass, (DLC) and tungsten carbide (WC), which have low contact angles, to suppress the phenomenon. CO, CO 2, or SiC gas may be generated when the inner wall 122, which is a portion where the mold 120 is made of only graphite material and directly contacts the molten material, is made of graphite material, and the generated SiC is formed on the surface of the quartz glass ingot A compressive stress may be applied to the surface of the quartz glass due to the difference in thermal expansion coefficient between the quartz glass and the graphite during cooling to cause cracks. However, when the inner wall 122 of the mold 120 ) Is made of materials such as diamond like carbon (DLC) and tungsten carbide (WC), so that this phenomenon can be suppressed. Since the inner wall 122 of the mold 120 is made of a material such as DLC (diamond like carbon) or tungsten carbide (WC), impurities can be prevented from being mixed in the molten material and the molten material and the graphite can be prevented from reacting The difference in thermal shrinkage during cooling due to the difference in coefficient of linear expansion between the large-area quartz glass ingot and the mold 120 is reduced, and the stress that the mold 120 compresses the large-area quartz glass ingot during cooling can be reduced have.

After the plurality of quartz glass ingots 180 are melted, they are cooled. The cooling may be performed by turning off the power of the heating means 130 so as to cool slowly in a natural state or to set the cooling rate by arbitrarily setting a temperature lowering rate (for example, 0.1 to 10 ° C / min). When cooling is performed at a too high speed, the stress at the time of cooling, which is generated based on the difference in coefficient of linear expansion between the large-area quartz glass ingot and the mold 120, is large, cracking or the like may occur in the large-area formed glass ingot, Therefore, it is preferable to slowly cool in the range of about 0.1 to 10 占 폚 / min. It is preferable that the cooling rate is much faster than the low temperature when cooling at a high temperature, and that the cooling rate is set by dividing it by temperature interval in consideration of this. For example, cooling is carried out at a holding temperature (for example, 1700 to 1900 ° C) to 1000 ° C at a rate of 5 to 10 ° C / min, cooling is carried out at a rate of 2 to 6 ° C / min to 1000 ° C to 300 ° C, And cooled at a rate of 0.1 to 1 占 폚 / min.

It is desirable to inject inert gas during cooling. A gas including high purity helium (He), argon (Ar), nitrogen (N 2 ), etc. may be used as the inert gas. The inert gas is preferably supplied at a flow rate of 1 to 20 slpm. If inert gas is injected during cooling, generation of reaction products is suppressed to obtain a large-area quartz glass ingot having high purity, and the cooling rate can be controlled.

After sufficient cooling, the mold 120 is unloaded from the chamber 110 and the large area quartz glass ingot is taken out of the mold 120.

The large-area quartz glass ingot thus produced has a shape corresponding to the shape of the mold 120 and has a larger area than the quartz glass ingot 180 used as a starting material.

The method described above can easily obtain a quartz glass ingot having a relatively large diameter and can obtain a large-area quartz glass ingot having a high homogeneity and a high quality. The large-area quartz glass ingot thus produced can be cut and used for various purposes such as an optical member have.

Hereinafter, experimental examples according to the present invention will be specifically shown, and the present invention is not limited by the following experimental examples.

<Experimental Example 1>

A large-area quartz glass ingot was produced using the apparatus shown in Fig. 1 and the mold shown in Fig.

Two quartz glass ingots were prepared for size-up (or large area). The quartz glass ingot had an OH group concentration of about 200 ppm. The weight of each of the quartz glass ingots was about 300 g.

Two quartz glass ingots were placed next to each other in the mold 120. The inner shape of the mold 120 was cylindrical as shown in Fig. 2, and an inner diameter of 8 cm and a height of 15 cm was used.

After accommodating the two quartz glass ingots in the mold 120, the upper part of the mold 120 was covered with the cover 190 and sealed.

A mold 120 containing two quartz glass ingots was charged into the chamber 110.

The pressure in the chamber 110 was reduced to 2 to 3 x 10 &lt; -2 &gt; Torr by using the evacuating device 150 to make the vacuum state.

The temperature in the chamber 110 was raised to 1750 DEG C and 1800 DEG C, respectively, and the temperature was maintained for 1 hour to melt the quartz glass ingot. The temperature rise was performed at a rate of 10 ° C / min up to 1200 ° C and at a rate of 5 ° C / min at a temperature range of 1200 ° C to 1750 ° C and 1200 ° C to 1800 ° C.

1750 ° C and 1800 ° C for 1 hour, and then cooled. The cooling causes the heating means 130 to be turned off and slowly cooled to a natural state. Nitrogen (N 2 ), which is an inert gas, was injected during cooling. During the cooling from 1750 ° C and 1800 ° C to 900 ° C, nitrogen (N 2 ) was injected to bring the pressure in the chamber to about 3 MPa. During the cooling from room temperature to 900 ° C, nitrogen (N 2 ) Was about 1 MPa.

After sufficient cooling, the mold 120 was unloaded from the chamber 110 and the large area quartz glass ingot was taken out of the mold 120.

<Experimental Example 2>

A large-area quartz glass ingot was produced using the apparatus shown in Fig. 1 and the mold shown in Fig.

Two quartz glass ingots were prepared for size-up (or large area). The quartz glass ingot had an OH group concentration of about 200 ppm. The weight of each of the quartz glass ingots was about 300 g.

Further, a quartz powder having a melting point lower than that of a plurality of quartz glass ingots used as a starting material was prepared. The quartz powder was an amorphous powder mainly composed of SiO 2 and having a thermal expansion coefficient of about 10 -6 / ° C. The quartz powder was dried in an oven at a temperature of about 100 DEG C for 8 hours before it was used as a starting material. The quartz powder having an average particle diameter of about 1 mu m was used, and an OH group concentration of about 100 ppm was used.

The quartz powder was uniformly distributed in the mold 120, and two quartz glass ingots were disposed adjacent to each other. The quartz powder was added in an amount of 0.167 part by weight based on 100 parts by weight of the total amount of the quartz glass ingot used as the starting material. The inner shape of the mold 120 was cylindrical as shown in Fig. 2, and an inner diameter of 8 cm and a height of 15 cm was used.

After the quartz powder and the two quartz glass ingots were accommodated in the mold 120, the upper part of the mold 120 was covered with the cover 190 and sealed.

A mold 120 containing quartz powder and two quartz glass ingots was charged into the chamber 110.

The pressure in the chamber 110 was reduced to 2 to 3 x 10 &lt; -2 &gt; Torr by using the evacuating device 150 to make the vacuum state.

The temperature in the chamber 110 was raised to 1750 DEG C and 1800 DEG C, respectively, and maintained for 1 hour to melt the quartz glass ingot. The temperature rise was performed at a rate of 10 ° C / min up to 1200 ° C and at a rate of 5 ° C / min at a temperature range of 1200 ° C to 1750 ° C and 1200 ° C to 1800 ° C.

1750 ° C and 1800 ° C for 1 hour, and then cooled. The cooling causes the heating means 130 to be turned off and slowly cooled to a natural state. Nitrogen (N 2 ), which is an inert gas, was injected during cooling. During the cooling from 1750 ° C and 1800 ° C to 900 ° C, nitrogen (N 2 ) was injected to bring the pressure in the chamber to about 3 MPa. During the cooling from room temperature to 900 ° C, nitrogen (N 2 ) Was about 1 MPa.

After sufficient cooling, the mold 120 was unloaded from the chamber 110 and the large area quartz glass ingot was taken out of the mold 120.

6 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1750 ° C for 1 hour according to Experimental Example 1, and FIG. 7 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1800 ° C for 1 hour 8 is a photograph showing a large-area quartz glass ingot manufactured by holding at 1750 ° C for 1 hour according to Experimental Example 2, and FIG. 9 is a photograph showing a large-area quartz glass ingot maintained at 1,800 ° C for 1 hour according to Experimental Example 2 This is a photograph showing a manufactured large-area quartz glass ingot.

6 to 9, it can be seen that pores are formed in the large-area quartz glass ingot produced according to Experimental Example 1. In the large-area quartz glass ingot produced according to Experimental Example 2, It can be seen that the porosity is smaller than that of the large - area quartz glass ingot produced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, This is possible.

110: chamber
120: mold
130: Heating means
140: gas supply unit
150: Exhaust system
160: gas outlet
170: gas inlet
180: Quartz glass ingot
190: Mold cover

Claims (13)

Disposing a plurality of quartz glass ingots as a starting material and quartz powder having a lower melting point than the quartz glass ingot in a mold;
Charging a mold containing the quartz powder and a plurality of the quartz glass ingots into the chamber;
Reducing the pressure in the chamber to less than atmospheric pressure to a vacuum state;
Heating and maintaining the temperature in the chamber to a temperature in the range of 1700 to 1900 ° C so that the quartz powder and the plurality of quartz glass ingots are melted; And
And cooling the quartz powder and the plurality of quartz glass ingots to melt,
The inner wall, which is a portion of the quartz glass ingot used as a starting material, which is in contact with the molten material is made of DLC (diamond like carbon) or tungsten carbide (WC) material, and the outer wall is made of a graphite material Lt; / RTI &gt;
A mold containing a plurality of quartz glass ingots is covered with a lid and sealed,
The inner portion of the quartz glass ingot used as a starting material is made of DLC (diamond like carbon) or tungsten carbide (WC), and the outer portion is made of a graphite material to serve as a self heating source In addition,
The quartz powder is dried in an oven to remove moisture and used as a starting material before being used as a starting material,
The quartz powder is added to the mold in an amount of 0.001 to 2 parts by weight based on 100 parts by weight of the total amount of the quartz glass ingot used as a starting material,
The quartz powder has a lower OH group concentration than the quartz glass ingot used as a starting material,
Wherein the quartz powder has a thermal expansion coefficient lower than that of a plurality of quartz glass ingots used as a starting material.
The method for producing a large-area quartz glass ingot according to claim 1, wherein a plurality of said quartz glass ingots have an OH group concentration of 10 to 2,000 ppm.
delete delete delete The method for producing a large-area quartz glass ingot according to claim 1, wherein the quartz powder has an average particle diameter of 100 nm to 500 m.
delete 2. The apparatus of claim 1, further comprising: a chamber;
A mold positioned within the chamber and acting as a self heating source;
A heating means for surrounding the periphery of the chamber and heating the mold by a high frequency induction heating method;
A gas supply unit for supplying an inert gas to the chamber;
An exhaust device for decompressing the pressure in the chamber to less than atmospheric pressure to make it in a vacuum state; And
Wherein the large-area quartz glass ingot is manufactured using an apparatus including a gas outlet for discharging the gas in the chamber.
9. The method of claim 8 wherein the inert gas is a gas containing helium (He), argon (Ar) or nitrogen (N 2) gas,
Wherein the inert gas is supplied at a flow rate of 1 to 20 slpm.
delete delete The method for producing a large-area quartz glass ingot according to claim 1, wherein the ingot is maintained at a temperature of 1700 to 1900 캜 for 30 to 120 minutes.
The method of manufacturing a large-area quartz glass ingot according to claim 1, wherein the cooling is gradual cooling in a range of 0.1 to 10 占 폚 / min.
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KR102523899B1 (en) * 2018-10-17 2023-04-20 주식회사 엘지화학 Apparatus for manufacturing glass
KR102132252B1 (en) 2019-03-07 2020-07-09 비씨엔씨 주식회사 Quartz reforming method
CN115108713B (en) * 2022-06-15 2024-01-26 江苏亨芯石英科技有限公司 Preparation process of quartz glass with high optical uniformity

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KR102416265B1 (en) 2020-08-27 2022-07-05 한국광기술원 Apparatus for Sealing Quartz Glass Ampoule
KR102566720B1 (en) 2022-12-23 2023-08-14 비씨엔씨 주식회사 Quartz reforming method

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